Treatment of infectious disease

ABSTRACT

The present disclosure relates to 2-(3-indolyl)indolin-3-one derivatives of the natural product isatisine A, synthesized from dual catalytic synthesis on metalocarbene-azide cascade chemistry, useful for treating a subject having or suspected of having an infectious disease, wherein said infectious disease is caused by a virus, wherein the virus is from the family flaviviridae or paramyxoviridae.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional PatentApplication No. 62/649,220, filed Mar. 28, 2018, which application isincorporated herein by reference in its entirety.

FIELD

The present disclosure relates generally to the treatment of infectiousdisease.

BACKGROUND

Annually, Respiratory Syncytial Virus (RSV) causes an estimated 3.4million severe lower respiratory infections requiring hospitalization inchildren under 5 years of agwe. Recent vaccine development efforts havenot been fruitful, and no licensed efficacious therapeutics areavailable to treat infection. A viral RNA-dependent RNA polymerasecomplex (RdRp), required for expression and replication of the viralgenome, provides an attractive target for inhibition of the viralreplication cycle. The absence of an X-ray crystal structure of thiscomplex rules out in silico approaches for inhibitor development.

ZIKV infection, in contrast to RSV, has only recently been identified asan unmet therapeutic need. The most recent severe ZIKV outbreak to dateoccurred in Brazil, with an estimated incidence of 30,000 infectionssince first detection in May 2015. While primary symptoms are usuallymild, the association of ZIKV infection with congenital microcephaly andits mosquito-based transmission underscore the importance of developingtherapeutics against it, especially from a prophylactic vantage point.Currently no vaccine or specific antiviral treatments are available forZIKV.

SUMMARY

In an aspect of the present application there is provided a compound offormula (I)

or

-   -   a stereoisomer, a racemate, a tautomer, a pharmaceutically        acceptable salt, a solvate, or a functional derivative thereof,    -   wherein:    -   R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀        alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl,        C₃-C₂₀ carbocycle, aryl, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol,        ether, ketone, carboxylic acid, ester, thiol, thioether, amine,        amide, carbamate, nitro, cyano, or halo, each of which is        optionally substituted;    -   R² is independently aryl, benzyl, or heterocycle, each of which        is optionally substituted; and    -   R³ and R⁴ are each independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl,        C₂-C₁₀ alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀        alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀        alkoxy, C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid,        ester, thiol, thioether, amine, amide, carbamate, nitro, cyano,        or halo, each of which is optionally substituted; or R³ and R⁴,        together with the atoms to which they are attached, are        connected to form a cycle or heterocycle, each of which is        optionally substituted.

In another aspect, there is provided a compound having the formula (II)

or

-   -   a stereoisomer, a racemate, a tautomer, a pharmaceutically        acceptable salt, a solvate, or a functional derivative thereof,    -   wherein:    -   Y is independently C or a heteroatom;    -   R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀        alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl,        C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy,        C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester,        thiol, thioether, amine, amide, carbamate, nitro, cyano, or        halo, each of which is optionally substituted;    -   R³ and R⁴ are each independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl,        C₂-C₁₀ alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀        alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀        alkoxy, C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid,        ester, thiol, thioether, amine, amide, carbamate, nitro, cyano,        or halo, each of which is optionally substituted; or R³ and R⁴,        together with the atoms to which they are attached, are        connected to form a cycle or heterocycle, each of which is        optionally substituted; and    -   R⁶ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl,        C₂-C₁₀ alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀        alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀        alkoxy, C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid,        ester, thiol, thioether, amine, amide, carbamate, nitro, cyano,        or halo, each of which is optionally substituted; or two of R⁶,        together with the atoms to which they are attached, are        connected to form a cycle or heterocycle, each of which is        optionally substituted; and wherein one Y is bonded to C₁ and        the corresponding R⁶ is absent.

In another aspect, there is provided a compound having the formula (III)

or

-   -   a stereoisomer, a racemate, a tautomer, a pharmaceutically        acceptable salt, a solvate, or a functional derivative thereof,

wherein:

Y and Y′ are each independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol,ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁶ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol,ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁶, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and wherein one Y′ is bonded to C₁ and thecorresponding R⁶ is absent.

In another aspect, there is provided a compound having the formula (IV)

or

-   -   a stereoisomer, a racemate, a tautomer, a pharmaceutically        acceptable salt, a solvate, or a functional derivative thereof,    -   wherein:    -   Y is independently C or a heteroatom;    -   R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀        alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl,        C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy,        C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester,        thiol, thioether, amine, amide, carbamate, nitro, cyano, or        halo, each of which is optionally substituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁷, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted.

In another aspect, there is provided a compound having the formula (V)

or

-   -   a stereoisomer, a racemate, a tautomer, a pharmaceutically        acceptable salt, a solvate, or a functional derivative thereof,    -   wherein:    -   Y is independently C or a heteroatom;    -   R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀        alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl,        C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy,        C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester,        thiol, thioether, amine, amide, carbamate, nitro, cyano, or        halo, each of which is optionally substituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted;

R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁷, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and,

R⁸ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol,ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁸, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted.

In another aspect, there is provided a compound having the formula (VI)

or

-   -   a stereoisomer, a racemate, a tautomer, a pharmaceutically        acceptable salt, a solvate, or a functional derivative thereof,    -   wherein:    -   R¹ is an ester;    -   R⁵ is a halo; and,    -   R⁸ is independently H, C₁-C₁₀ alkoxy, or halo, each of which is        optionally substituted.

In an embodiment of the present application, there is provided acompound having the structure

In another embodiment, there is provided a compound having the structure

In another aspect of the present application, there is provided a methodof synthesizing a compound as described herein, comprising:

-   -   a) reacting an organoazide-dizaoketone compound with a        transition metal catalyst;    -   b) forming a metallocarbene from the reaction of the        organoazide-dizaoketone compound with a transition metal        catalyst;    -   c) generating an electrophilic C-acylimine from the        metallocarbene; and,    -   d) reacting the electrophilic C-acylimine with a nucleophilic        compound.

In an embodiment of the present application, there is provided a methodwherein step d) further comprises reacting the electrophilic C-acyliminewith a nucleophilic compound in the presence of a Bronsted acidcatalyst.

In another embodiment, there is provided a method wherein the transitionmetal catalyst is a

Cu catalyst. In another embodiment, the transition metal catalyst isCu(hfacac)₂, Cu(OTf)₂, or CuOTf.Ph(CH₃).

In another embodiment, there is provided a method wherein thenucleophilic compound is a heteroatom-containing compound. In anotherembodiment, the heteroatom-containing compound is a heterocycle or acycle substituted with a heteroatom-containing moiety. In anotherembodiment, the heterocycle is pyrrole, furan, thiophene, pyridine,indole, benzofuran, benzothiphene, imidazole, or derivatives thereof,each of which is optionally substituted.

In another aspect of the present application, there is provided apharmaceutical composition comprising a compound as described herein, ora compound syntheized by the method as described herein, and apharmaceutically acceptable carrier, diluent, or vehicle.

In another aspect of the present application, there is provided a methodof treating a subject having or suspected of having an infectiousdisease, comprising: administering a therapeutically effective amount ofa compound as described herein, or a compound syntheized by the methodas described herein, or a pharmaceutical composition as describedherein.

In another aspect of the present application, there is provided a methodof treating a subject having or suspected of having an infectiousdisease, comprising: administering a therapeutically effective amount ofa compound as described herein, or a compound syntheized by the methodas described herein, or a pharmaceutical composition as describedherein, wherein said infectious disease is caused by a virus.

In another embodiment of the present application, there is provided amethod wherein said virus is a virus from the family Flaviviridae. Inanother embodiment, the virus is from the genera Hepacivirus,Flavivirus, Pegivirus, or Pestivirus. In another embodiment, Flavivirusis yellow fever virus (YFV), Japanese encephalitis virus (JEV),Tick-borne encephalitis virus (TBEV), Dengue virus (DENV), West Nilevirus (WNV), Zika virus (ZIKAV), or any combination thereof.

In another embodiment, there is provided a method wherein said virus isfrom the family Paramyxoviridae. In another embodiment, said virus isfrom the genera Paramyxovirus, Pneumovirus, or Morbillivirus. In anotherembodiment, Paramyxovirus is parainfluenza virus or mumpus virus. Inanother embodiment, Pneumovirus is respiratory syncytial virus (RSV). Inanother embodiment, said Morbillivirus is measles virus.

In another embodiment, there is provided a method wherein said subjectis a human, a domesticated animal, livestock, a laboratory animal, anon-human mammal, a non-human primate, a rodent, a bird, a reptile, anamphibian, or a fish. In some cases, the individual to be treated with amethod of the present disclosure is a human. In some cases, theindividual to be treated with a method of the present disclosure is anungulate (e.g., a bovine; an ovine; a caprine; an equine; etc.).

In another aspect of the present application, there is provided a use ofa compound of as described herein, or a compound syntheized by themethod as described herein, or a pharmaceutical composition as describedherein for treating a subject having or suspected of having aninfectious disease.

In another aspect of the present application, there is provided a use ofa compound as described herein, or a compound syntheized by the methodas described herein, or a pharmaceutical composition as described hereinin the manufacture of a medicament for treating a subject having orsuspected of having an infectious disease.

In another aspect of the present application, there is provided a use ofa compound as described herein, or a compound syntheized by the methodas described herein, or a pharmaceutical composition as described hereinfor treating a subject having or suspected of having an infectiousdisease, wherein said infectious disease is caused by a virus.

In another aspect of the present application, there is provided a use ofa compound as described herein, or a compound syntheized by the methodas described herein, or a pharmaceutical composition as described hereinin the manufacture of a medicament for treating a subject having orsuspect of having an infectious disease, wherein said infectious diseaseis caused by a virus.

In another embodiment of the present application, there is provided ause wherein said virus is a virus from the family Flaviviridae. Inanother embodiment, the virus is from the genera Hepacivirus,Flavivirus, Pegivirus, or Pestivirus. In another embodiment, Flavivirusis yellow fever virus (YFV), Japanese encephalitis virus (JEV),Tick-borne encephalitis virus (TBEV), Dengue virus (DENV), West Nilevirus (WNV), Zika virus (ZIKAV), or any combination thereof.

In another embodiment of the present application, there is provided ause wherein said virus is a virus from the family Paramyxoviridae. Inanother embodiment, said virus is from the genera Paramyxovirus,Pneumovirus, or Morbillivirus. In another embodiment, Paramyxovirus isparainfluenza virus or mumpus virus. In another embodiment, Pneumovirusis respiratory syncytial virus (RSV). In another embodiment, saidMorbillivirus is measles virus.

In another embodiment of the present application, there is provided ausewherein said subject is a human, a domesticated animal, livestock, alaboratory animal, a non-human mammal, a non-human primate, a rodent, abird, a reptile, an amphibian, or a fish.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the present disclosure will now be described, by way ofexample only, with reference to the attached Figures.

FIG. 1 depicts a one-step synthesis of Isatisine A analogs;

FIG. 2 depicts redox activation of Cu(OTf)₂ and dual catalysis;

FIG. 3 depicts asymmetric induction by chiral Bronsted acid;

FIG. 4 depicts an extension of coupling conditions to other2-Indolylindolin-3-ones;

FIG. 5 depicts infectivity and cytotoxicity results;

FIG. 6 depicts a series of second generation 2-Indolylindan-3-ones;

FIG. 7 depicts differential scanning calorimetry (DSC) data for compound1a;

FIG. 8 depicts thermogravimetric analysis (TGA) data for compound 1a;

FIG. 9 depicts an in-situ IR spectroscopic analysis of decomposition ofcompound 1a;

FIG. 10 depicts decomposition analysis of compound 1a, in the presenceof Cu (I) catalyst, using NMR;

FIG. 11 depicts UV-VIS spectra of solution A (Example 2);

FIG. 12 depicts electrospray mass spectra of crude reaction mixture tomake compound 2a;

FIG. 13 depicts an ORTEP structure for compound 1a;

FIG. 14 depicts an ORTEP structure for compound 2a;

FIG. 15 depicts an ORTEP structure for compound 2o;

FIG. 16 depicts an ORTEP structure for compound 2za;

FIG. 17 depicts an NMR spectrum of compound 1c;

FIG. 18 depicts an NMR spectrum of compound 1f;

FIG. 19 depicts an NMR spectrum of compound 1h;

FIG. 20 depicts an NMR spectrum of compound 1j;

FIG. 21 depicts an NMR spectrum of compound 1k;

FIG. 22 depicts an NMR spectrum of compound 1l;

FIG. 23 depicts an NMR spectrum of compound 2a;

FIG. 24 depicts an NMR spectrum of compound 2b;

FIG. 25 depicts an NMR spectrum of compound 2c;

FIG. 26 depicts an NMR spectrum of compound 2d;

FIG. 27 depicts an NMR spectrum of compound 2e;

FIG. 28 depicts an NMR spectrum of compound 2f;

FIG. 29 depicts an NMR spectrum of compound 2h;

FIG. 30 depicts an NMR spectrum of compound 2i;

FIG. 31 depicts an NMR spectrum of compound 2j;

FIG. 32 depicts an NMR spectrum of compound 2k;

FIG. 33 depicts an NMR spectrum of compound 2l;

FIG. 34 depicts an NMR spectrum of compound 2m;

FIG. 35 depicts an NMR spectrum of compound 2n;

FIG. 36 depicts an NMR spectrum of compound 2o;

FIG. 37 depicts an NMR spectrum of compound 2p;

FIG. 38 depicts an NMR spectrum of compound 2q;

FIG. 39 depicts an NMR spectrum of compound 2s;

FIG. 40 depicts an NMR spectrum of compound 2t;

FIG. 41 depicts an NMR spectrum of compound 2u;

FIG. 42 depicts an NMR spectrum of compound 2v;

FIG. 43 depicts an NMR spectrum of compound 2w;

FIG. 44 depicts an NMR spectrum of compound 2xa:2xb;

FIG. 45 depicts an NMR spectrum of compound 2ya:2yb;

FIG. 46 depicts an NMR spectrum of compound 2za;

FIG. 47 depicts an NMR spectrum of compound 5a;

FIG. 48 depicts an NMR spectrum of compound 5b;

FIG. 49 depicts an NMR spectrum of compound 5c;

FIG. 50 depicts an NMR spectrum of compound 5d;

FIG. 51 depicts an NMR spectrum of compound 5e;

FIG. 52 depicts an NMR spectrum of compound 5f;

FIG. 53 depicts an NMR spectrum of compound 5g; and

FIG. 54 depicts an NMR spectrum of compound 5h.

FIG. 55 depicts homology modelling of a Respiratory Syncytial Virus(RSV) L protein based on the VSV L structure. Model of RSV L protein(left), Alignment of the RSV model with L protein of VSV. (VSV:Vesicular Stomatitis Virus).

FIG. 56 depicts molecular docking of an active compound (compound 5a) ofthe present disclosure into the active site of RSV L protein showing twohydrogen bonds to the catalytic ASP 686. Active site was defined usingbinding site map implanted in Schrödinger Small Molecule DiscoverySuite.

FIG. 57A-57B provide an amino acid sequence of human RSV-L protein (SEQID NO:1).

DETAILED DESCRIPTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs.

As used in the specification and claims, the singular forms “a”, “an”and “the” include plural references unless the context clearly dictatesotherwise.

The term “comprising” as used herein will be understood to mean that thelist following is non-exhaustive and may or may not include any otheradditional suitable items, for example one or more further feature(s),component(s) and/or ingredient(s) as appropriate.

As used herein, the term ‘optionally substituted’ refers to beingsubstituted or unsubstituted.

As used herein, the term “unsubstituted” refers to any open valence ofan atom being occupied by hydrogen. Also, if an occupant of an openvalence position on an atom is not specified then it is hydrogen.

As used herein, the term “substituted” refers to having one or moresubstituents or substituent moieties whose presence either facilitatesor improves a desired reaction/property, or does not impede a desiredreaction/property. A “substituent” is an atom or group of bonded atomsthat can be considered to have replaced one or more hydrogen atomsattached to a parent molecular entity; and, whose presence eitherfacilitates or improves desired reactions, properties, and/or functionsof an invention, or does not impede desired reactions, properties,and/or functions of an invention. Examples of substituents includealkyl, alkenyl, alkynyl, aryl, polycyclic aryl, benzyl, polycyclicbenzyl, fused aromatic rings, arylhalide, heteroaryl, polycyclicheteroaryl, fused heteroaromatic rings, cycloalkyl (non-aromatic ring),halo, alkoxyl, perfluoronated alkoxyl, amino, alkylamino, alkenylamino,amide, amidine, hydroxyl, thioether, alkylcarbonyl, alkylcarbonyloxy,arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carbonate,alkoxycarbonyl, aminocarbonyl, alkylthiocarbonyl, phosphate, phosphateester, phosphonato, phosphinato, cyano, acylamino, imino, sulfhydryl,alkylthio, arylthio, thiocarboxylate, dithiocarboxylate, sulfate,sulfato, sulfonate, sulfamoyl, sulfonamide, Si(alkyl)₃, Si(alkoxy)₃,nitro, nitrile, azido, heterocyclyl, ether, ester, silicon-containingmoieties, thioester, or a combination thereof. The substituents maythemselves be substituted. For instance, an amino substituent may itselfbe mono or independently disubstituted by further substituents providedabove, such as alkyl, alkenyl, alkynyl, aryl, aryl-halide, heteroaryl,cycloalkyl (non-aromatic ring).

As used herein, “alkyl” refers to a linear or branched saturatedhydrocarbon moiety that consists solely of single-bonded carbon andhydrogen atoms, which can be unsubstituted or substituted with one ormore substituents. Examples of saturated straight or branched chainalkyl groups include, but are not limited to, methyl, ethyl, 1-propyl,2-propyl, 1-butyl, 2-butyl, 2-methyl-1-propyl, 2-methyl-2-propyl,1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-1-butyl, 3-methyl-1-butyl,2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 1-hexyl, 2-hexyl, 3-hexyl,2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl,2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl,2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl and 2-ethyl-1-butyl,1-heptyl, and 1-octyl.

As used herein, “alkenyl” refers to a linear or branched hydrocarbonmoiety that comprises at least one carbon to carbon double bond, whichcan be unsubstituted or substituted with one or more substituents.“Alkynyl” refers to a linear or branched hydrocarbon moiety thatcomprises at least one carbon to carbon triple bond, which can beunsubstituted or substituted with one or more substituents.

The term “carbocycle” as used herein refers to a non-aromatic, saturatedor partially saturated monocyclic or polycyclic hydrocarbon ring moietycontaining at least 3 carbon atoms. Examples of C₃-C_(n) carbocyclesinclude, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, adamantyl,bicyclo[2.2.2]oct-2-enyl, and bicyclo[2.2.2]octyl.

As used herein, “aryl” and/or “aromatic ring” refers to an aromatic(unsaturated cyclic) hydrocarbon moiety having 6 to 100 atoms, or 6 to50 atoms, or 6 to 25 atoms, or 6 to 15 atoms, which can be unsubstitutedor substituted with one or more substituents. The aromatic hydrocarbonmoiety may be derived from benzene or a benzene derivative; may bemonocyclic or polycyclic, where polycyclic may include a fused ringsystem. Examples include, but are not limited to, phenyl, naphthyl,xylene, phenyl ethane, substituted phenyl, substituted naphthyl,substituted xylene, substituted 4-ethylphenyl, benzyl, etc.

As used herein, “cycle” refers to an aromatic or nonaromatic monocyclic,polycyclic, or fused ring hydrocarbon moiety, which can be substitutedor unsubstituted. Included within the term “cycle” are carbocycles andaryls, as defined above.

As used herein, “heteroaryl” or “heteroaromatic” refers to an aryl(including fused aryl rings) that includes heteroatoms selected fromoxygen, nitrogen, sulfur, and phosphorus. A “heteroatom” refers to anatom that is not carbon or hydrogen, such as nitrogen, oxygen, sulfur,or phosphorus. Heteroaryl or heteroaromatic groups include, for example,furanyl, thiophenyl, pyrrolyl, imidazoyl, benzamidazoyl, 1,2- or1,3-oxazolyl, 1,2- or 1,3-diazolyl, 1,2,3- or 1,2,4-triazolyl, and thelike.

As used herein, a “heterocycle” is an aromatic or nonaromaticmonocyclic, polycyclic, or fused ring moiety of carbon atoms and atleast one heteroatom, or 1 to 4 heteroatoms, or 1 to 10 heteroatoms. A“heteroatom” refers to an atom that is not carbon or hydrogen, such asnitrogen, oxygen, sulfur, or phosphorus. Included within the term“heterocycle” is “heteroaryl”, which refers to an aromatic (unsaturatedcyclic) moiety of carbon atoms and at least one heteroatom, or 1 to 4heteroatoms, or 1 to 10 heteroatoms, having a total of 6 to 100 atoms,or 6 to 50 atoms, or 6 to 25 atoms, or 6 to 15 atoms, which can beunsubstituted or substituted with one or more substituents. Alsoincluded within this term are monocyclic and bicyclic rings that includeone or more double and/or triple bonds within the ring. Examples of 3-to 9-membered heterocycles include, but are not limited to, furanyl,thiophenyl, pyrrolyl, imidazoyl, benzamidazoyl, 1,2- or 1,3-oxazolyl,1,2- or 1,3-diazolyl, 1,2,3- or 1,2,4-triazolyl, aziridinyl, oxiranyl,thiiranyl, azirinyl, diaziridinyl, diazirinyl, oxaziridinyl, azetidinyl,azetidinonyl, oxetanyl, thietanyl, piperidinyl, piperazinyl,morpholinyl, pyrrolyl, oxazinyl, thiazinyl, diazinyl, triazinyl,tetrazinyl, imidazolyl, benzimidazolyl, tetrazolyl, indolyl,isoquinolinyl, quinolinyl, quinazolinyl, pyrrolidinyl, purinyl,isoxazolyl, benzisoxazolyl, furanyl, furazanyl, pyridinyl, oxazolyl,benzoxazolyl, thiazolyl, benzthiazolyl, thiophenyl, pyrazolyl,triazolyl, benzodiazolyl, benzotriazolyl, pyrimidinyl, isoindolyl andindazolyl.

As used herein, “halo” refers to F, Cl, Br, I.

The term “subject”, as used herein, refers to an animal, and caninclude, for example, domesticated animals, such as cats, dogs, etc.,livestock (e.g., cattle, horses, pigs, sheep, goats, etc.), laboratoryanimals (e.g., mouse, rabbit, rat, guinea pig, etc.), mammals, non-humanmammals, primates, non-human primates, rodents, birds, reptiles,amphibians, fish, and any other animal. In a specific example, thesubject is a human.

The term “treatment”, “treat”, or “treating” as used herein, refers toobtaining beneficial or desired results, including clinical results.Beneficial or desired clinical results can include, but are not limitedto, alleviation or amelioration of one or more symptoms or conditions,diminishment of extent of disease, stabilized (i.e. not worsening) stateof disease, preventing spread of disease, delay or slowing of diseaseprogression, amelioration or palliation of the disease state,diminishment of the reoccurrence of disease, and remission (whetherpartial or total), whether detectable or undetectable. “Treating” and“Treatment” can also mean prolonging survival as compared to expectedsurvival if not receiving treatment.

The term “amelioration” or “ameliorates” as used herein refers to adecrease, reduction or elimination of a condition, disease, disorder, orphenotype, including an abnormality or symptom.

The term “functional derivative” as used herein refers to a moleculethat retains a biological activity (either function or structural) thatis substantially similar to that of the original compound. A functionalderivative or equivalent may be a natural derivative or is preparedsynthetically.

Also encompassed is prodrug or “physiologically functional derivative”.The term “physiologically functional derivative” as used herein refersto compounds which are not pharmaceutically active themselves but whichare transformed into their pharmaceutically active form in vivo, i.e. inthe subject to which the compound is administered. The term “prodrug” asused herein, refers to a derivative of a substance that, followingadministration, is metabolized in vivo, e.g. by hydrolysis or byprocessing through an enzyme, into an active metabolite.

In some cases, a compound of the present disclosure inhibits enzymaticactivity of an RNA polymerase (e.g., an RNA-dependent RNA polymerase)encoded by an RNA virus. For example, in some cases, a compound of thepresent disclosure inhibits enzymatic activity of an RNA polymerase byat least 10%, at least 20%, at least 30%, at least 40%, at least 50%, atleast 60%, at least 70%, at least 80%, at least 90%, at least 95%, atleast 98%, at least 99%, or 100%, compared to the enzymatic activity ofthe RNA polymerase in the absence of the compound.

An RNA polymerase (e.g., an RNA-dependent RNA polymerase) that can beinhibited by a compound of the present disclosure can be an RNApolymerase encoded by any of the following RNA viruses: a Coronaviridaevirus, a Picornaviridae virus, a Caliciviridae virus, a Flaviviridaevirus, a Togaviridae virus, a Bornaviridae, a Filoviridae, aParamyxoviridae, a Pneumoviridae, a Rhabdoviridae, an Arenaviridae, aBunyaviridae, an Orthomyxoviridae, a Deltavirus, Coronavirus, SARScoronavirus, MERS coronavirus, Poliovirus, Rhinovirus, Hepatitis Avirus, Hepatitis B virus, Norwalk virus, Yellow fever virus, West Nilevirus, Hepatitis C virus, Dengue fever virus, Zika virus, Rubella virus,Ross River virus, Sindbis virus, Chikungunya virus, Borna disease virus,Ebola virus, Marburg virus, Measles virus, Mumps virus, Nipah virus,Hendra virus, Newcastle disease virus, Human respiratory syncytialvirus, Rabies virus, Lassa virus, Hantavirus, Crimean-Congo hemorrhagicfever virus, Influenza virus (e.g., swine influenza virus; avianinfluenza virus; H1N1, H3N2, H7N9, H5N1, etc.), porcine respiratory andreproductive disease syndrome virus (PRRSV), Seneca valley virus,porcine epidemic diarrhea virus (PEDV), porcine delta coronavirus(PDCV), porcine circoviral associated diseases (PCVAD), and Hepatitis Dvirus. In some cases, the RNA polymerase that is inhibited by a compoundof the present disclosure is encoded by Zika virus. In some cases, theRNA polymerase that is inhibited by a compound of the present disclosureis encoded by Ebola virus. In some cases, the RNA polymerase that isinhibited by a compound of the present disclosure is encoded by humanrespiratory syncytial virus (RSV). In some cases, the RNA polymerasethat is inhibited by a compound of the present disclosure is encoded bybovine RSV.

RNA-dependent RNA polymerases (RdRP) are known in the art. In somecases, an RNA polymerase (e.g., an RNA-dependent RNA polymerase) that isinhibited by a compound of the present disclosure comprises an aminoacid sequence having at least 20%, at least 30%, at least 40%, at least50%, at least 60%, at least 70%, at least 80%, at least 90%, at least95%, at least 98%, at least 99%, or 100%, with the amino acid sequencedepicted in FIG. 57A-57B. In some cases, the RNA-dependent RNApolymerase comprises an Asp at a position corresponding to 686 of theamino acid sequence depicted in FIG. 57A-57B.

The present disclosure provides methods of treating a viral infection,the methods comprising administering to an individual having the viralinfection a therapeutically effective amount of a compound of thepresent disclosure, or a composition comprising a compound of thepresent disclosure.

As used herein, the term “therapeutically effective amount” refers to anamount that is effective for preventing, ameliorating, or treating adisease or disorder (e.g., an infection disease, such as a viraldisease).

In some cases, a therapeutically effective amount of a compound of thepresent disclosure is an amount that is effective to reduce the amountof virus in a tissue, organ, or fluid in an individual being treated.For example, in some cases, a therapeutically effective amount of acompound of the present disclosure is an amount that is effective toreduce the amount of virus in a tissue, organ, or fluid in an individualbeing treated by at least 10%, at least 20%, at least 30%, at least 40%,at least 50%, at least 60%, at least 70%, at least 80%, or more than80%, compared to the amount of virus present in the tissue, organ, orfluid in the individual before treatment with the compound.

In an aspect, there is described a compound, compositions, methods, anduses, for the treatment of a subject having, or suspected of having, aninfectious disease.

In an example the infectious disease is caused by a virus.

Viral infections that can be treated with a method of the presentdisclosure include infections caused by any of the following: aCoronaviridae virus, a Picornaviridae virus, a Caliciviridae virus, aFlaviviridae virus, a Togaviridae virus, a Bornaviridae, a Filoviridae,a Paramyxoviridae, a Pneumoviridae, a Rhabdoviridae, an Arenaviridae, aBunyaviridae, an Orthomyxoviridae, a Deltavirus, Coronavirus, SARS,Poliovirus, Rhinovirus, Hepatitis A virus, Hepatitis B virus, Norwalkvirus, Yellow fever virus, West Nile virus, Hepatitis C virus, Denguefever virus, Zika virus, Rubella virus, Ross River virus, Sindbis virus,Chikungunya virus, Borna disease virus, Ebola virus, Marburg virus,Measles virus, Mumps virus, Nipah virus, Hendra virus, Newcastle diseasevirus, Human respiratory syncytial virus, bovine respiratory syncytialvirus, Rabies virus, Lassa virus, Hantavirus, Crimean-Congo hemorrhagicfever virus, Influenza virus (e.g., swine influenza virus; avianinfluenza virus; etc.), porcine respiratory and reproductive diseasesyndrome virus (PRRSV), Seneca valley virus, porcine epidemic diarrheavirus (PEDV), porcine delta coronavirus (PDCV), porcine circoviralassociated diseases (PCVAD), and Hepatitis D virus. In some cases, theviral infection is caused by a positive-strand RNA virus. In some cases,the viral infection is caused by a negative-strand RNA virus.

In an example, the virus is from the family Flaviviridae. In anotherexample, the virus I from the genera Hepacivirus, Flavivirus, Pegivirus,or Pestivirus

Non-limiting examples of flavivirus include yellow fever virus (YFV),Japanese encephalitis virus (JEV), Tick-borne encephalitis virus (TBEV),Dengue virus (DENV), West Nile virus (WNV), Zika virus (ZIKAV), or anycombination thereof.

In a specific example, the viral infection is Zika virus.

In an example, the virus is from the family of Paramyxoviridae. Inanother example, the virus is from the genera Paramyxovirus,Pneumovirus, or Morbillivirus

Non-limiting example of paramyxovirus include parainfluenza virus andmumpus virus.

Non-limiting examples of Pneumovirus include respiratory syncytial virus(RSV).

Non-limiting examples of Morbillivirus include measles virus.

In a specific example, the viral infection is respiratory syncytialvirus (RSV). As one example, in some cases, the viral infection is humanRSV. As another example, in some cases, the viral infection is bovineRSV.

In another aspect, there is described a compound of formula (I)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylicacid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, orhalo, each of which is optionally substituted;

R² is independently aryl, benzyl, or heterocycle, each of which isoptionally substituted; and

R³ and R⁴ are each independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or R³ and R⁴, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted.

In an example, there is described a compound having the formula (II)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

Y is independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol,ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R³ and R⁴ are each independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or R³ and R⁴, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁶ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁶, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and wherein one Y is bonded to C1 and thecorresponding R⁶ is absent.

In another example, there is described a compound having the formula(III)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

Y and Y′ are each independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol,ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁶ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol,ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁶, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and wherein one Y′ is bonded to C₁ and thecorresponding R⁶ is absent.

In another example, there is described a compound having the formula(IV)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

Y is independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl,benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁷, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted.

In another example, there is described a compound having the formula (V)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

Y is independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted;

R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁷, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and,

R⁸ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁸, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted.

In another example, there is described a compound having the formula(VI)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

R¹ is an ester;

R⁵ is a halo; and,

R⁸ is independently H, C₁-C₁₀ alkoxy, or halo, each of which isoptionally substituted.

In some examples, the compounds as described herein have the structure

In some examples, the compounds as described herein have the structure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In other examples, the compounds as described herein have any one of thestructure

In another example, the absolute stereochemistry of the quaternarystereocentre (chiral carbon) of the compounds as described herein may beR, S, or a mixture of R and S.

In another example, when the compounds as described herein comprise twoor more stereocentres (chiral carbons), the absolute stereochemistry maybe any permutation of R and S, or a mixture of any permutation.

In another aspect, there is described a method of synthesizing thecompounds as described herein, the method comprising:

-   -   a) reacting an organoazide-dizaoketone compound with a        transition metal catalyst;    -   b) forming a metallocarbene from the reaction of the        organoazide-dizaoketone compound with a transition metal        catalyst;    -   c) generating an electrophilic C-acylimine from the        metallocarbene; and,    -   d) reacting the electrophilic C-acylimine with a nucleophilic        compound.

In an example, of the method as described herein step d) furthercomprises reacting the electrophilic C-acylimine with a nucleophiliccompound in the presence of a Bronsted acid catalyst.

In another example of the method as described herein, the transitionmetal catalyst is a Cu catalyst. In another example, the transitionmetal catalyst is Cu(hfacac)₂, Cu(OTf)₂, or CuOTf.Ph(CH₃).

In another example of the method as described herein, the nucleophiliccompound is a heteroatom-containing compound. In another example theheteroatom-containing compound is a heterocycle or a cycle substitutedwith a heteroatom-containing moiety. In another example, the heterocycleis pyrrole, furan, thiophene, pyridine, indole, benzofuran,benzothiphene, imidazole, or derivatives thereof, each of which isoptionally substituted.

In some examples, the compounds as described herein are an enantiomer, aracemate, a tautomer, or a pharmaceutically acceptable salt, or asolvate, or a functional derivative thereof.

In some examples, there is described a composition comprising a compoundas described herein, and a pharmaceutically acceptable carrier, diluent,or vehicle.

A compound or composition may be administered alone or in combinationwith other treatments, either simultaneously or sequentially, dependentupon the condition to be treated.

In treating a subject, a therapeutically effective amount may beadministered to the subject.

Formulations may conveniently be presented in unit dosage form and maybe prepared by any methods known in the art. Such methods include thestep of bringing the active compound into association with a carrier,which may constitute one or more accessory ingredients. In general, theformulations are prepared by uniformly and intimately bringing intoassociation the active compound with liquid carriers or finely dividedsolid carriers or both, and then if necessary shaping the product.

The compounds and compositions may be administered to a subject by anyconvenient route of administration, whether systemically/peripherally orat the site of desired action, including but not limited to, oral (e.g.by ingestion); topical (including e.g. transdermal, intranasal, ocular,buccal, and sublingual); pulmonary (e.g. by inhalation or insufflationtherapy using, e.g. an aerosol, e.g. through mouth or nose); rectal;vaginal; parenteral, for example, by injection, including subcutaneous,intradermal, intramuscular, intravenous, intraarterial, intracardiac,intrathecal, intraspinal, intracapsular, subcapsular, intraorbital,intraperitoneal, intratracheal, subcuticular, intraarticular,subarachnoid, and intrasternal; by implant of a depot, for example,subcutaneously or intramuscularly.

Compounds and/or compositions comprising compounds disclosed herein maybe used in the methods described herein in combination with standardtreatment regimes, as would be known to the skilled worker.

Methods of the invention are conveniently practiced by providing thecompounds and/or compositions used in such method in the form of a kit.Such kit preferably contains the composition. Such a kit preferablycontains instructions for the use thereof.

Examples of Non-Limiting Aspects of the Disclosure

Aspects, including embodiments, of the present subject matter describedabove may be beneficial alone or in combination, with one or more otheraspects or embodiments. Without limiting the foregoing description,certain non-limiting aspects of the disclosure numbered 1-41 areprovided below. As will be apparent to those of skill in the art uponreading this disclosure, each of the individually numbered aspects maybe used or combined with any of the preceding or following individuallynumbered aspects. This is intended to provide support for all suchcombinations of aspects and is not limited to combinations of aspectsexplicitly provided below:

Aspect 1. A compound of formula (I)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylicacid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, orhalo, each of which is optionally substituted;

R² is independently aryl, benzyl, or heterocycle, each of which isoptionally substituted; and R³ and R⁴ are each independently H, C₁-C₁₀alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl,C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester,thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, eachof which is optionally substituted; or R³ and R⁴, together with theatoms to which they are attached, are connected to form a cycle orheterocycle, each of which is optionally substituted.

Aspect 2. The compound of aspect 1, having the formula (II)

or

-   -   a stereoisomer, a racemate, a tautomer, a pharmaceutically        acceptable salt, a solvate, or a functional derivative thereof,

wherein:

Y is independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl,benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R³ and R⁴ are each independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or R³ and R⁴, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁶ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁶, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and wherein one Y is bonded to C₁ and thecorresponding R⁶ is absent.

Aspect 3. The compound of aspect 1 or 2, having the formula (III)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

Y and Y′ are each independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl,benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁶ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁶, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and wherein one Y′ is bonded to C1 and thecorresponding R⁶ is absent.

Aspect 4. The compound of any one of aspects 1 to 3, having the formula(IV)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

Y is independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and

R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁷, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted.

Aspect 5. The compound of any one of aspects 1 to 4, having the formula(V)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

Y is independently C or a heteroatom;

R¹ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl,benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted;

R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁵, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted;

R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy,alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine,amide, carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁷, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted; and,

R⁸ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl,C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle,aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether,ketone, carboxylic acid, ester, thiol, thioether, amine, amide,carbamate, nitro, cyano, or halo, each of which is optionallysubstituted; or two of R⁸, together with the atoms to which they areattached, are connected to form a cycle or heterocycle, each of which isoptionally substituted.

Aspect 6. The compound of any one of aspects 1 to 5, having the formula(VI)

or

a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptablesalt, a solvate, or a functional derivative thereof,

wherein:

R¹ is an ester;

R⁵ is a halo; and,

R⁸ is independently H, C₁-C₁₀ alkoxy, or halo, each of which isoptionally substituted.

Aspect 7. The compound of any one of aspects 1 to 6, having thestructure

Aspect 8. The compound of any one of aspects 1 to 4, having thestructure

Aspect 9. A method of synthesizing a compound of any one of aspects 1 to8, comprising:

-   -   a) reacting an organoazide-dizaoketone compound with a        transition metal catalyst    -   b) forming a metallocarbene from the reaction of the        organoazide-dizaoketone compound with a transition metal        catalyst;    -   c) generating an electrophilic C-acylimine from the        metallocarbene; and    -   d) reacting the electrophilic C-acylimine with a nucleophilic        compound.

Aspect 10. The method of aspect 9, wherein step d) further comprisesreacting the electrophilic C-acylimine with a nucleophilic compound inthe presence of a Bronsted acid catalyst.

Aspect 11. The method of aspect 9 or 10, wherein the transition metalcatalyst is a Cu catalyst.

Aspect 12. The method of aspect 11, wherein the transition metalcatalyst is Cu(hfacac)₂, Cu(OTf)₂, or CuOTf.Ph(CH₃).

Aspect 13. The method of any one of aspects 9 to 12, wherein thenucleophilic compound is a heteroatom-containing compound.

Aspect 14. The method of aspect 13, wherein the heteroatom-containingcompound is a heterocycle or a cycle substituted with aheteroatom-containing moiety.

Aspect 15. The method of aspect 14, wherein the heterocycle is pyrrole,furan, thiophene, pyridine, indole, benzofuran, benzothiphene,imidazole, or derivatives thereof, each of which is optionallysubstituted.

Aspect 16. A pharmaceutical composition comprising a compound of any oneof aspects 1 to 8, or a compound syntheized by the method of any one ofaspects 8 to 15, and a pharmaceutically acceptable carrier, diluent, orvehicle.

Aspect 17. A method of treating a subject having or suspected of havingan infectious disease, comprising: administering a therapeuticallyeffective amount of a compound of any one of aspects 1 to 8, or acompound syntheized by the method of any one of aspects 8 to 15, or apharmaceutical composition of aspect 16.

Aspect 18. A method of treating a subject having or suspected of havingan infectious disease, comprising: administering a therapeuticallyeffective amount of a compound of any one of aspects 1 to 8, or acompound syntheized by the method of any one of aspects 8 to 15, or apharmaceutical composition of aspect 16, wherein said infectious diseaseis caused by a virus.

Aspect 19. The method of aspects 18, wherein said virus is a virus fromthe family Flaviviridae.

Aspect 20. The method of aspect 19, wherein the virus is from the generaHepacivirus, Flavivirus, Pegivirus, or Pestivirus.

Aspect 21. The method of aspect 20, wherein said flavivirus is yellowfever virus (YFV), Japanese encephalitis virus (JEV), Tick-borneencephalitis virus (TBEV), Dengue virus (DENV), West Nile virus (WNV),Zika virus (ZIKAV), or any combination thereof.

Aspect 22. The method of aspect 18, wherein said virus is from thefamily Paramyxoviridae.

Aspect 23. The method of aspect 22, wherein said virus is from thegenera Paramyxovirus, Pneumovirus, or Morbillivirus.

Aspect 24. The method of aspect 23, wherein Paramyxovirus isparainfluenza virus or mumpus virus.

Aspect 25. The method of aspect 23, wherein said Pneumovirus isrespiratory syncytial virus (RSV).

Aspect 26. The method of aspect 23, wherein said Morbillivirus ismeasles virus.

Aspect 27. The method of any one of aspects 17 to 26, wherein saidsubject is a human, a domesticated animal, livestock, a laboratoryanimal, a non-human mammal, a non-human primate, a rodent, a bird, areptile, an amphibian, or a fish.

Aspect 28. Use of a compound of any one of aspects 1 to 8, or a compoundsyntheized by the method of any one of aspects 8 to 15, or apharmaceutical composition of aspect 16 for treating a subject having orsuspected of having an infectious disease.

Aspect 29. Use of a compound of any one of aspects 1 to 8, or a compoundsyntheized by the method of any one of aspects 8 to 15, or apharmaceutical composition of aspect 16 in the manufacture of amedicament for treating a subject having or suspected of having aninfectious disease.

Aspect 30. Use of a compound of any one of aspects 1 to 8, or a compoundsyntheized by the method of any one of aspects 8 to 15, or apharmaceutical composition of aspect 16 for treating a subject having orsuspected of having an infectious disease, wherein said infectiousdisease is caused by a virus.

Aspect 31. Use of a compound of any one of aspects 1 to 8, or a compoundsyntheized by the method of any one of aspects 8 to 15, or apharmaceutical composition of aspect 16 in the manufacture of amedicament for treating a subject having or suspect of having aninfectious disease, wherein said infectious disease is caused by avirus.

Aspect 32. The use of aspect 30 or 31, wherein said virus is a virusfrom the family Flaviviridae.

Aspect 33. The use of aspect 32, wherein the virus is from the generaHepacivirus, Flavivirus, Pegivirus, or Pestivirus.

Aspect 34. The use of aspect 33, wherein said flavivirus is yellow fevervirus (YFV), Japanese encephalitis virus (JEV), Tick-borne encephalitisvirus (TBEV), Dengue virus (DENV), West Nile virus (WNV), Zika virus(ZIKAV), or any combination thereof.

Aspect 35. The use of aspect 30 or 31, wherein said virus is a virusfrom the family Paramyxoviridae.

Aspect 36. The use of aspect 35, wherein said virus is from the generaParamyxovirus, Pneumovirus, or Morbillivirus.

Aspect 37. The use of aspect 36, wherein Paramyxovirus is parainfluenzavirus or mumpus virus.

Aspect 38. The use of aspect 36, wherein said Pneumovirus is respiratorysyncytial virus (RSV).

Aspect 39. The use of aspect 36, wherein said Morbillivirus is measlesvirus.

Aspect 40. The use of any one of aspects 28 to 39, wherein said subjectis a human, a domesticated animal, livestock, a laboratory animal, anon-human mammal, a non-human primate, a rodent, a bird, a reptile, anamphibian, or a fish.

Aspect 41. A method of inhibiting an RNA-dependent RNA polymerase (RdRP)of an RNA virus, the method comprising contacting the RdRP with acompound according to any one of aspects 1-8.

EXAMPLES

To gain a better understanding of the invention described herein, thefollowing examples are set forth. It should be understood that theseexamples are for illustrative purposes only. Therefore, they should notlimit the scope of this invention in anyway.

Example 1 Dual Catalytic Synthesis of Antiviral Compounds Based onMetal-Locarbene-Azide Cascade Chemistry

Aryl azides trapped ortho metallocarbene intermediates to generateindolenones possessing a reactive C-acylimine moiety, which reacted withadded indole nucleophiles to afford a 2-(3-indolyl)indolin-3-onescaffold found in antiviral natural product isatisine A. This overallprocess occurred through a dual catalytic sequence at room temperature.Redox activation of a Cu(OTf)₂ precatalyst by indole resulted incatalytically competent Cu(I) required for azide-metallocarbenecoupling. A Bronsted acid that formed from Cu(OTf)₂ reduction wasresponsible for catalysis of the C—C bond-forming indole addition step.This modular method allowed for rapid assembly of bis(indole) libraries,several of which demonstrated anti-infective activity againstrespiratory syncytial virus and Zika virus.

Reaction sequences proceeding through high-energy reactiveintermediates, generated catalytically, can offer an approach for rapidconstruction of structurally complex products. Metallocarbenes generatedfrom diazoketone precursors can be intercepted by a variety ofnucleophilic heteroatom-containing functionalities to afford ylideintermediates that then undergo rearrangement processes. Use of anorganoazide functionality to trap metallocarbene intermediates presentsan alternative approach for strategic assembly of substitutedheterocyclics. This process is catalyzed by inexpensive coppercatalysts, with two equivalents of nitrogen gas being the onlyby-products generated, and C-acylimines formed from this coupling aresubject to further reaction via in situ intermolecular nucleophilictrapping to give highly substituted indolin-3-one products through aone-pot cascade process. This process delivers a nucleophilic addendadjacent to one or more carbonyl moieties in umpollung fashion. Indoleswere found to be an especially effective class of traps, and it wasnoted that there are structural similarities between these bis(indole)adducts to isatisine A, a naturally occurring compound with antiviralproperties.

Given the modular nature of thediazoketone→metallocarbene→C-acylimine→indole adduct cascade sequence,construction of a library of unnatural Isatisine A-inspired bis(indole)compounds lacking a ribose-derived ‘eastern’ fragment was undertaken(see FIG. 1). Such compounds were screened for their potential activityagainst viral diseases for which there are no effective chemotherapeutictreatments, such as Respiratory Syncytial Virus (RSV; a well-studied andwidely disseminated pathogen) and Zika Virus (ZIKV; an emerging pathogenof great concern).

Experimental Details

Reactions were carried out in oven (130° C.) or flame-dried glasswareunder a positive argon atmosphere unless otherwise stated. Transfer ofanhydrous reagents was accomplished with oven-dried syringes orcannulae. Solvents were distilled before use: acetonitrile (CH₃CN),dichloromethane (DCM) and dichloroethane (DCE) from calcium hydride,toluene (PhMe) from sodium metal, diethyl ether (Et₂O) andtetrahydrofuran (THF) from sodium metal/benzophenone ketyl. Thin layerchromatography was performed on glass plates pre-coated with 0.25 mmsilica gel with fluorescent indicator UV₂₅₄ (Rose Scientific). Flashchromatography columns were packed with 230-400 mesh silica gel(Silacycle). Proton nuclear magnetic resonance spectra (¹H NMR) wererecorded at 400 MHz, or 500 MHz and coupling constants (J) are reportedin Hertz (Hz). Carbon nuclear magnetic resonance spectra (¹³C NMR) wererecorded at 125 MHz, as proton decoupled or as attached proton test(APT). Chemical shifts are reported on a 6 scale (ppm) and referenced toresidual solvent peaks: CDCl₃ (7.26 ppm, ¹H; 77.06 ppm, ¹³C), d₆-DMSO(2.49 ppm, ¹H; 39.5 ppm, ¹³C), and d₂-DCM (5.32 ppm, ¹H; 53.5 ppm, ¹³C).

All reagents were purchased from commercial suppliers: Sigma Aldrich, AKScientific, and Acros, at purity greater than (95%). Nuclear MagneticResonance (NMR) measurements (chemical shift, integration, couplingconstants, relative peak intensity) were performed using Agilent 400MHz, Varian 400 MHz, or Varian 500 MHz NMR instruments. Massmeasurements were acquired using Agilent Technologies 1100 MSD (SingleQuadruple), Waters (Micromass) Q-TOF Premier (Quadruple TOF), KratosAnalytical MS-50G, Agilent Technologies 6220 oaTOF, or AB Sciex QTRAP2000 instruments. UV-VIS spectra were acquired using Cary UV-Vis, orHewlett Packard 8453 UV-VIS Spectrometers. Elemental Analysis wasperformed using Thermo Flash 2000 Elemental Analyzer. Infrared spectrawere acquired using Mattson Galaxy Series FT-IR 3000, Nicolet Magna 750FTIR Spectrometer equipped a Nic-Plan FTIR Microscope, or Thermo Nicolet8700 FTIR Spectrometer equipped with a Continuum FTIR Microscope.Differential Scanning calorimetry and Thermogravimetric analysis wereperformed using Perkin Elmer Pyris 1, or Mettler Toledo TGA/DSCinstruments.

For virology procedures: MEM media (HyClone, GE Healthcare LifeSciences); Opti-MEM media (Gibco, Thermofisher); fetal bovine serum(FBS) (Gibco, Thermofisher); DMEM (HyClone, GE Healthcare LifeSciences); Methanol (HPLC Grade, Fisher Chemical); Acetone (ACSCertified, Fisher Chemical); Goat anti-RSV polyclonal antibody (MeridianLife Science B65860G); Alexafluor 647 (LifeTech A-21469); MTT((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide));Phosphate buffered saline (PBS) (Gibco, Thermofisher); Dimethylsulfoxide (DMSO) (ACS Certified, Fisher Chemical); [a 32-P] UTP waspurchased from PerkinElmer. All remaining reagents (actinomycin D,lysolecithin, Tris-acetate, Magnesium acetate, Potassium acetate, DTT,spermidine, creatine phosphatase, aprotinin, creatine phosphokinase,ATP, GTP, CTP, UTP, and RNaseH) were purchased from Sigma Aldrich atpurity greater than (95%).

Substrate Preparation

Preparation of compounds 1a, 1b, 1d, and 1g have been reportedpreviously by Bott, T. M.; Atienza, B. J.; West, F. G. RSC Adv. 2014, 4,31955-31959.

Dichloromethane (DCM, 35 mL) was added to a conical flask containing4,5-dimethoxy-2-azido benzoic acid (1.0 g, 4.5 mmol) and the suspensionwas cooled to 0° C. before addition of methyl acetate (1.0 equiv) andtrichloroacetyl chloride (1.2 equiv). This solution was slowlytransferred via cannula to a suspension of NaH (1.2 equiv) in DCM (10-20mL) at 0° C. After stirring at 0° C. for 15 min, the solution was cooledto −45° C. before addition of 1-methylimidazole (1.2 equiv). Thesolution was then stirred for an additional 10 min at −45° C. beforeslowly adding TiCl₄ (3.4 equiv) followed by NEt₃ (4.0 equiv). The darkred-brown solution was kept at −78° C. for 30 min before being warmed to0° C. and kept for 1 h and subsequently quenched with water (30 mL). Theorganic layer was separated and aqueous layer was washed 3x with equalportions of DCM. The combined organic layers were washed with anequivalent volume of water and brine, dried over MgSO₄, filtered, andconcentrated under reduced pressure. Crude product was partiallypurified by flash chromatography to afford an orange oil whose R_(f) wasabout 0.3 (7:3 hexanes:EtOAc). The orange oil was concentrated and addedto a stirred solution of triethylamine (1.2 equiv) in CH₃CN (20 mL).Tosyl azide (1.0 equiv) in CH₃CN (10 mL) was transferred via cannulainto the flask and the reaction was left to stir overnight.Concentration under reduced pressure followed by purification via flashchromatography (silica gel, 8:2 hexanes:Et0Ac→7:3 hexanes:EtOAc slowlyadded in gradient) furnished lc as a yellow oil in 50% yield (fromstarting 4,5-dimethoxy-2-azidobenzoic acid).

R_(f)=0.25 (7:3 hexanes:EtOAc); IR (cast film) 2978, 2134, 1711, 1695,1565, 1292 cm⁻¹; ¹H NMR (500 MHz, CDCl₃) δ 6.87 (s, 1H), 6.62 (s, 1H),3.94 (s, 3H), 3.86 (s, 3H), 3.78 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ184.5, 161.2, 152.4, 146.4, 131.4, 121.9, 111.6, 101.5, 56.3, 56.2,52.3; HRMS calc'd for C₁₂H₁₁N₅O₅Na [M+Na]⁺328.0652, found 328.0651.(NB.: ¹³C signal for the diazo carbon was not detected due toquadrupolar broadening.).

Prepared analogously to 1c using 3-nitro-2-azido benzoic acid in placeof 2-azido-4,5-dimethoxybenzoic acid. Isolated as a brown oil in 23%yield: R_(f)=0.19 (7:3 hexanes:EtOAc); IR (cast film) 3022, 2141, 1732,1694, 1637, 1567, 1293 cm⁻¹; ¹H NMR (500 MHz, CDCl₃) δ 8.14 (dd, J=8.2,1.6 Hz, 1H), 7.51 (dd, J=7.6, 1.6 Hz, 1H), 7.38 (dd, J=8.2, 7.6 Hz, 1H),3.76 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ 184.2, 160.5, 135.8, 132.7,132.5, 132.4, 127.8, 125.8, 52.6; LC-MS calc'd for C_(1o)H₇N₆O₅[M+H]⁺291.1, found 291.1. (NB.: (a) preparation for this startingmaterial was limited to 70-100 mg; (b) ¹³C signal for the diazo carbonwas not detected due to quadrupolar broadennin).

Prepared analogously to lc using 3-azido-2-napthoic acid in place of2-azido-4,5-dimethoxybenzoic acid.

Isolated as a brown oil in 51% yield: R_(f)=0.68 (7:3 hexanes:EtOAc); IR(cast film) 2971, 2136, 1724, 1693, 1633, 1567, 1290 cm⁻¹; ¹H NMR (500MHz, CDCl₃) δ 7.83-7.76 (m, 3H), 7.53 (br s, 1H), 7.54 (ddd, J=8.2, 6.9,1.2 Hz, 1H), 7.24 (ddd, J=8.2, 7.0, 1.2 Hz, 1H), 3.74 (s, 3H); ¹³C NMR(125 MHz, CDCl₃) δ 185.6, 160.9, 135.2, 134.7, 130.3, 129.5, 128.9,128.7, 128.4, 126.7, 126.2, 115.6, 52.3; HRMS calc'd for C₁₄H₉N₅O₃Na[M+Na]⁺318.0597, found 318.0594. (NB.: ³C signal for the diazo carbonwas not detected due to quadrupolar broadening.).

Prepared analogously to lc using vinyl acetate in place of methylacetate, and using 2-azido benzoic acid in place of2-azido-4,5-dimethoxy benzoic acid.

Isolated as a yellow oil in 46% yield: R_(f)=0.51 (7:3 hexanes:EtOAc);IR (cast film) 2924, 2931, 2136, 1724, 1684 cm⁻¹; ¹H NMR (400 MHz,CDCl₃) 6 7.47 (ddd, J=8.1, 7.5, 1.6 Hz, 1H), 7.28-7.25 (m, 1H),7.17-7.12 (m, 3H), 4.70 (dd, J=13.9, 2.0 Hz, 1H), 4.54 (dd, J=6.2, 2.0Hz, 1H); ¹³C NMR (125 MHz, CDCl₃) δ 185.3, 157.7, 140.1, 137.9, 132.2,130.2, 128.6, 124.8, 118.3, 98.5; HRMS calc'd for C₁₁H₇N₅O₃Na[M+Na]⁺280.0441, found 280.0439. (NB.: ¹³C signal for the diazo carbonwas not detected due to quadrupolar broadening.).

Prepared analogously to lc using (+)-menthyl acetate in place of methylacetate, and using 2-azido-benzoic acid in place of2-azido-4,5-dimethoxy benzoic acid.

Isolated as a yellow oil in 48% yield: R_(f)=0.64 (7:3 hexanes:EtOAc);[α]_(D) ²⁰ : −67.76 (c=0.52, DCM) IR (cast film) 2956, 2928, 2870, 2130,1719, 1691, 1302, 958 cm⁻¹; ¹HNMR (500 MHz, CDCl₃) δ 7.45 (ddd, J=8.1,7.4, 1.7 Hz, 1H), 7.30-7.28 (m, 1H), 7.19-7.14 (m, 2H), 4.70 (ddd,J=10.9, 10.9, 4.4, 1H), 2.00-1.96 (m, 1H), 1.71-1.58 (m, 3H), 1.44-1.36(m, 1H), 1.15-0.93 (m, 2H), 0.87 (d, J=6.5 Hz, 3H), 0.83 (d, J=7.0 Hz,3H), 0.87-0.83 (m, 2H), 0.72 (d, J=7.0 Hz, 3H); ¹³C NMR (125 MHz, CDCl₃)δ 185.9, 160.3, 137.6, 131.7, 130.8, 128.3, 124.7, 118.1, 75.9, 46.9,40.9, 34.0, 31.3, 26.4, 23.4, 21.9, 20.7, 16.3; HRMS calc'd forC₁₉H₂₃N₅O₃Na [M+Na]⁺392.1693, found 392.1692. (NB.: ¹³C signal for thediazo carbon was not detected due to quadrupolar broadening.).

Prepared analogously to lc using 2-azido-3-bromo benzoic acid in placeof 2-azido-4,5-dimethoxybenzoic acid. Product was obtained in 43% yield(unoptimized due to procedure being run only once, on a sufficient scaleto permit its use in multiple coupling experiments).

Isolated as a yellow oil: R_(f)=0.64 (3:7, EtOAc:hexanes); IR (castfilm) 3026, 2955, 2111, 1729, 1634, 1585, 1565 cm⁻¹; ¹H NMR (500 MHz,CDCl₃): δ 7.35-7.33 (m, 2H), 7.18 (d, J=8.5 Hz, 1H), 3.78 (s, 3H); ¹³CNMR (125 MHz, CDCl₃): δ 184.7, 160.7, 139.2, 129.7, 129.2, 128.0, 125.7,121.5, 52.4; HRMS calc'd for C₁₀H₆BrN₅NaO_(3 [)M+Na]⁺345.9546, found345.9549. (NB.: ¹³C signal for the diazo carbon was not detected due toquadrupolar broadening.).

A solution of LiHMDS (6.2 mL of 1M THF solution; 6.2 mmol) was added toa solution of 2-azido-acetophenone (1.0 g, 6.2 mmol) in 10 mL THF at−78° C. The mixture was allowed to stir for 30 min. Then, a solution ofbenzoyl cyanide (822 mg, 6.20 mmol, dissolved in 10 mL THF) was addeddropwise. The mixture was allowed to stir for 1 h then quenched withsaturated NH₄Cl (15 mL). The mixture was diluted with diethyl ether (10mL). The organic layer was separated and washed with water (20 mL, 3×).The organic layer was washed with brine and dried with MgSO₄. Thesolution was concentrated under pressure to afford yellow oil. Theyellow oil was purified using flash column chromatography eluting 10% %EtOAc in hexanes to furnish 1.13 g (69%) of intermediate β-diketone(isolated as an enol) as a yellow oil:

R_(f)=0.63 (7:3 hexanes:EtOAc); IR (cast film) 3064, 2420, 2125, 1599,1281, 1604, 778, 1126, 750 cm⁻¹; ¹H NMR (500 MHz, CDCl₃) δ 8.01-7.87 (m,3H), 7.59-7.48 (m, 4H), 7.28-6.99 (m, 2H), 7.00 (s, 1H); ¹³C NMR (125MHz, CDCl₃,) δ 185.5, 184.4, 138.3, 135.4, 132.6, 132.5, 130.4, 128.7,128.3, 127.3, 125.0, 119.3, 98.3; HRMS calc'd for C₁₁H₁₁N₃O₂[M]⁺265.0851, found: 294.0849. (NB.: enol H was not detected.)

Triethylamine (715 μL, 5.1 mmol) was added to a stirred solution of theintermediate diketone (500 mg, 1.89 mmol) in CH₃CN (8 mL). Tosyl azide(400 mg, 2.00 mmol) in CH₃CN (5 mL) was transferred via cannula into theflask and the reaction was left to stir overnight. Concentration underreduced pressure followed by purification via flash chromatography(silica gel, 7:3 hexanes:EtOAc) resulted in a quantitative yield of11(551 mg) as a pale yellow oil. To prevent decomposition, product wasstored under Ar in a freezer in a foil wrapped flask. Under theseconditions the compound was stable over several months.

R_(f)=0.71 (7:3 hexanes:EtOAc); IR (cast film) 3053, 2451, 2132, 1641,1283, 1607, 779, 1136, 754 cm⁻¹; ¹H NMR (500 MHz, CDCl₃) δ 7.55-7.53 (m,2H), 7.43-7.28 (m, 5H), 7.13 (ddd, J=7.6, 7.6, 0.8 Hz, 1H), 6.92 (d,J=8.0 Hz, 1H); ¹³C NMR (125 MHz, CDCl₃) δ 185.9, 184.9, 137.5, 136.7,132.5, 132.5, 130.0, 129.5, 128.2, 128.0, 125.0, 118.2, 98.3; LC-MScalc'd for C₁₅H₉N₅O₂ [M+H]⁺291.2, found: 291.2.

Dual-Catalytic Formation of Bis(Indole) Products 2 and 5

Representative Procedure for Small-Scale Synthesis of 2a (Method A):

A solution of diazoazide 1a (0.250 g, 1.02 mmol) in DCM (25 mL) wasadded to a solution of indole (0.239 g, 2.04 mmol) and Cu(OTf)₂ (37 mg,0.102 mmol) in DCM (25 mL) at room temperature via syringe pump over 1h. The reaction mixture turned light green over 1-2 h and slowly turneddark brown over 24 h. Once addition was complete, the reaction wasmonitored by TLC for consumption of 1a, (for some diazoazide startingmaterials, the reaction mixture was heated further at reflux for 10-15minutes to ensure completion). Upon consumption of 1a, the reactionmixture was concentrated under reduced pressure, purified by flashchromatography (silica gel, 7:3 hexanes:EtOAc), and recrystallization(MeOH) (See Example 2 for more details). Total isolated yield of 2a was0.287 g (92%), as a combined yellow amorphous powder and crystals.Suitable single crystals of 2a for X-ray diffraction were grown from 1:1MeOH-EtOAc via slow evaporation of solvent.

Representative Procedure for Gram-Scale Synthesis of 2a (Method B):

A solution of diazoazide 1a (5.00 g, 20.4 mmol) in DCM (150-250 mL) wasadded to a solution of indole (4.78 g, 40.8 mmol) and Cu(OTf)₂ (740 mg,2.04 mmol) in DCM (150-250 mL) at room temperature via syringe pump. Thereaction mixture turned light green over 2 h and slowly turned darkbrown with suspended green solid over 24 h. The reaction was monitoredby TLC for consumption of 1a. Upon consumption of 1a, the suspendedsolid was filtered from the reaction mixture to afford green needles of2a. The green needles were directly recrystallized with minimum amountof ethyl acetate (hot), followed by slow addition of pentane or hexaneto furnish adduct 2a as a fine dark yellow solid in 74% (69-78%) yield.The mother liquor contained ca. 10% of the product and could still bepurified by flash chromatography (silica gel, 7:3 Hexanes:EtOAc) toafford yellow oil, which precipitated when left standing at −4° C.overnight.

Following Method A, 0.231 g (74%) of dark yellow crystalline 2a wasisolated after recrystallization. Concentration of mother liquorafforded another 0.056 g (18%) of yellow/brown amorphous powder.Combined total of 2a was 0.287 g (92%), m.p. ˜110° C. (typical for theyellow/brown powder), m.p.=225-226° C. (crystals); IR (cast film) 3392,3059, 2953, 1726, 1697, 1491, 1434, 1214, 748 cm¹; ¹H NMR (500 MHz,CDCl₃) δ 8.22 (br s, 1H), 7.70 (d, J=7.7 Hz, 1H), 7.59 (d, J=8.3 Hz,1H), 7.53 (app td, J=8.3, 1.3 Hz, 1H), 7.40 (d, J=2.4 Hz, 1H), 7.37 (d,J=8.1 Hz, 1H), 7.20 (app t, J=7.2 Hz, 1H), 7.11 (app t, J=7.9 Hz, 1H),7.01 (d, J=8.3 Hz, 1H), 6.93 (app t, J=7.7 Hz, 1H), 5.73 (br s, 1H),3.80 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) 193.3, 168.5, 159.5, 140.4,136.5, 127.8, 125.3, 123.5, 122.8, 121.4, 120.5, 119.4, 115.1, 112.6,111.7, 111.2, 73.0, 53.9; HRMS calc'd for C₁₈H₁₅N₂O_(3 [)M+H]⁺307.1077,found 307.1078; Elemental analysis calc'd for C₁₈H₁₄N₂O₃: 70.58% C,4.61% H, 9.15% N, 15.67% O, found, 70.48% C, 4.62% H, 9.13%N. ¹H-NMRspectral data were in good agreement with those reported in theliterature [Jessing, M.; Barran, P. S. Heterocycles 2011, 82,1739-1745]. ¹³C-NMR spectral varied by up to 0.6 ppm for some ¹³C NMRresonances. There were also additional three carbon resonances reportedhere not included in the earlier data. Similar to ¹H-NMR spectralcharacterizations, IR wavenumbers were likewise in good agreement.

(Method A) Isolated as yellow cubic crystals in 89% yield (usingmethanol as crystallizing solvent): m.p.=215-216° C. (reported forpowder 82° C. [Jessing, M.; Barran, P.S. Heterocycles 2011, 82,1739-1745] and [Bolt, T. M.; Atienza, B. J.; West, F. G. RSC Adv. 2014,4, 31955-31959]); R_(f)=0.31 (yellow spot, 7:3 hexanes:EtOAc); IR (castfilm) 3366, 3051, 1744, 1702, 1616, 1485, 1293, 742 cm⁻¹; ¹H NMR (500MHz, CDCl₃): δ 7.73 (d, J=7.0 Hz, 1H), 7.62 (d, J=7.5 Hz, 1H), 7.54 (appt, J=6.5 Hz, 1H), 7.34 (d, J=8.0 Hz, 1H), 7.30 (d, J=5.5 Hz, 1H), 7.27(app t, J=7.0 Hz, 1H), 7.14 (app t, J=7.0 Hz, 1H), 7.00 (d, J=8.0 Hz,1H), 6.96 (app t, J=6.8 Hz, 1H), 5.34 (br s, 1H), 3.84 (s, 3H), 3.77 (s,3H); ¹³C NMR (125 MHz, CDCl₃): δ 195.2, 169.1, 161.0, 137.9, 137.4,128.0 126.0, 125.4, 122.3, 120.4, 120.0, 119.9, 119.5, 113.6, 109.8,109.8, 72.4, 53.8, 32.9; HRMS calc'd for C₁₉H₁₇N₂O₃ [M+H]⁺321.1234,found 321.1233.

(Method A) Isolated as a yellow crystalline solid in 93% combined yield(Method B: 77-83% yield if direct recrystallization from crude reactionmixture using methanol as the solvent): m.p.=181-183° C.; R_(f)=0.40(yellow spot, 7:3 hexanes:EtOAc); IR (cast film) 3370, 3051, 2920, 1742,1704, 1616, 1486, 743 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 7.72 (d, J=7.7Hz, 1H), 7.64 (d, J=7.9 Hz, 1H), 7.55 (ddd, J=8.3, 7.2, 1.3 Hz, 1H),7.42 (s, 1H), 7.32-7.25 (m, 4H), 7.20 (app td, J=8.3, 1.0 Hz, 1H),7.15-7.11 (m, 3H), 7.02 (d, J=8.3 Hz, 1H), 6.95 (app t, J=7.9 Hz, 1H),5.79 (br s, 1H), 5.30 (s, 2H), 3.83 (s, 3H); ¹³C NMR (125 MHz, CDCl₃): δ194.7, 169.0, 161.0, 137.9, 137.0, 136.9, 128.8, 127.7, 127.6, 126.9,126.3, 125.4, 122.4, 120.4, 120.2, 119.9, 119.8, 113.6, 110.5, 110.3,72.4, 53.8, 50.4; HRMS calc'd for C₂₅H₂₀N₂O₃Na [M+Na]⁺419.1366, found:419.1363; Fluorescent properties in methanol solution: excitationwavelengths at 290 nm and 395 nm, emission wavelength at 500 nm (bothexcitation wavelength).

(Method A) Isolated as a bright yellow microcrystals in 88% yield;m.p.=127° C. (decomp.); R_(f)=0.28 (yellow spot, 7:3 hexanes:EtOAc); IR(cast film) 3360, 3062, 2950, 1710, 1617, 1487, 1239, 748 cm⁻¹; ¹H NMR(500 MHz, CDCl₃): δ 8.29 (br s, 1H), 7.66 (br d, J=8.1 Hz, 1H), 7.57(ddd, J=8.4, 7.2, 1.5 Hz, 1H), 7.48-7.46 (m, 2H), 7.42-7.37 (m, 3H),7.35 (d, J=8.1 Hz, 1H), 7.23 (d, J=8.3 Hz, 1H), 7.20 (ddd, J=8.3, 7.2,1.1 Hz, 1H), 7.05 (ddd, J=8.3, 7.2, 1.1 Hz, 1H), 7.00 (d, J=8.3 Hz, 1H),6.97 (app t, J=7.9 Hz, 1H), 5.62 (br s, 1H), 3.24 (s, 3H); ¹³C NMR (125MHz, CDCl₃): δ 195.1, 168.8, 160.8, 138.0, 137.9, 135.5, 132.5, 129.6,128.8, 128.4, 126.8, 125.2, 122.7, 120.6, 120.4, 120.2, 119.7, 113.4,111.2, 108.2, 73.3, 53.2; HRMS calc'd for C₂₄H₁₉N₂O₃[M+H]⁻383.1390,found 383.1385.

(Method A) Isolated as a light green crystalline solid in 71% yield;m.p.=242-243° C.; R_(f)=0.23 (yellow spot, 7:3 hexanes:EtOAc); IR(microscope) 3365, 3006, 2953, 1726, 1706, 1610, 1488, 1219, 792 cm⁻¹;¹H NMR (500 MHz, d⁶-DMSO): 6 7.60 (br s, 1H), 7.55 (d, J=7.9 Hz, 1H),7.51 (app t, J=8.3 Hz, 1H), 7.45 (d, J=7.9 Hz, 1H), 7.27 (d,J=7.5 Hz,1H), 7.10 (d, J=2.8 Hz, 1H), 7.06 (app t, J=7.9 Hz, 1H), 7.04 (d, J=8.3Hz, 1H), 6.81 (app t, J=7.5 Hz, 1H), 3.61 (s, 3H) (Note: one NH protonwas not detected); ¹³C NMR (125 MHz, d⁶-DMSO): δ 195.9, 169.9, 162.2,138.6 (2×), 126.4, 125.1, 125.0, 124.0, 123.3, 118.9, 118.0, 114.0,113.0, 112.1, 111.4, 72.4, 53.5; HRMS calc'd for C₁₈H₁₄⁷⁹BrN₂O₃[M+H]⁺385.0182, found 385.0182; Elemental analysis calc'd forC₁₈H₁₃BrN₂O₃: 56.12% C, 3.40% H, 7.27% N; found, 55.98% C, 3.41% H,7.24% N.

(Method A) Isolated as bright yellow crystals in 78% yield;m.p.=186-188° C.; R_(f)=0.11 (yellow spot, 7:3 hexanes:EtOAc); IR (castfilm) 3301, 3060, 2947, 1742, 1685, 1487, 1232, 1218, 756 cm⁻¹; ¹H NMR(500 MHz, CDCl₃): δ 8.19 (br s, 1H), 7.74 (dd, J=7.9, 0.6 Hz, 1H), 7.56(app td, J=8.3, 1.3 Hz, 1H), 7.38 (d, J=2.6 Hz, 1H), 7.30-7.26 (m, 2H),7.06-7.04 (m, 2H), 6.98 (app t, J=7.2 Hz, 1H), 6.89 (dd, J=8.8, 2.4 Hz,1H), 5.71 (br s, 1H), 3.81 (s, 3H), 3.77 (s, 3H); ¹³C NMR (125 MHz,CDCl₃): δ 194.9, 169.0, 161.0, 154.4, 137.9, 131.7, 125.8, 125.4, 124.3,120.4, 120.0, 113.5, 112.7, 112.3, 111.2, 101.5, 72.4, 55.8, 53.7; HRMScalc'd for C₁₉H₁₇N₂O₄ [M+H]⁺337.1183, found 337.1185.

(Method A, with following modification: after addition of diazo-azide 1aby syringe pump, reaction mixture was heated to reflux and stirred atthat temperature until consumption of 1a was observed) Isolated as ayellow oil in 46% yield; R_(f)=0.40 (yellow spot, 7:3 hexanes:EtOAc); IR(cast film) 3363, 3065, 2954, 1748, 1711, 1617, 1488, 1242, 751 cm⁻¹; ¹HNMR (500 MHz, CDCl₃): δ 7.69 (d, J=7.9 Hz, 1H), 7.55 (dd, J=7.7, 0.6 Hz,1H), 7.54 (ddd, J=8.3, 7.2, 1.3 Hz, 1H), 7.45 (dd, J=8.1, 0.6 Hz, 1H),7.28 (app td, J=7.2, 1.3 Hz, 1H), 7.21 (app td, J=7.9, 1.1 Hz, 1H), 7.03(d, J=8.3 Hz, 1H), 6.95 (overlapped app td, J=7.7, 0.6 Hz, 1H), 6.94(overlapped s, 1H), 5.74 (br s, 1H), 3.85 (s, 3H); ¹³C NMR (125 MHz,CDCl₃): δ 191.3, 166.6, 161.2, 155.0, 150.9, 138.2, 127.7, 125.7, 124.9,123.1, 121.6, 120.8, 119.3, 113.7, 111.3, 105.6, 71.9, 54.2; HRMS calc'dfor C₁₈H₁₃NO₄Na [M+Na]⁺330.0737, found 330.0739.

(Method A) Isolated as a yellow oil in 68% yield: R_(f)=0.34 (yellowspot, 7:3 hexanes:EtOAc); IR (cast film) 3426, 3390, 3056, 2954, 1726,1697, 1488, 1233, 751 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 9.43 (br s, 1H),7.63 (d, J=7.9 Hz, 1H), 7.56 (apparent (app) td, J=7.5, 1.5 Hz, 1H),7.09 (d, J=7.5 Hz, 1H), 6.94 (app td, J=7.2, 0.7 Hz, 1H), 6.87 (app td,J=2.6, 1.7 Hz, 1H), 6.33 (ddd, J=3.5, 2.7, 1.7 Hz, 1H), 6.19-6.14 (m,1H), 5.68 (br s, 1H), 3.84 (s, 3H); ¹³C NMR (125 MHz, CDCl₃): 8 193.2,167.6, 161.6, 138.0, 125.8, 124.8, 120.7, 119.2, 118.8, 113.6, 108.2,106.3, 71.8, 53.9; HRMS calc'd for C₁₄H₁₃N₂O₃[M+H]⁺257.0921, found257.0915.

(Method A, with following modification: after addition of diazoazide 1aby syringe pump, the reaction mixture was heated to reflux and stirredat that temperature until consumption of 1a was observed) Isolated as ayellow oil in 48% yield; R_(f)=0.37 (yellow spot, 7:3 hexanes:EtOAc); IR(cast film) 3362, 3125, 2954, 1748, 1710, 1617, 1488, 1233, 751 cm⁻¹; ¹HNMR (500 MHz, CDCl₃): δ 7.69 (d, J=7.2 Hz, 1H), 7.55 (app td, J=7.2, 0.9Hz, 1H), 7.44 (dd, J=1.8, 0.9 Hz, 1H), 7.03 (d, J=8.3 Hz, 1H), 6.96 (appt, J=7.7 Hz, 1H), 6.56 (d, J=3.3 Hz, 1H), 6.42 (dd, J=3.3, 1.9 Hz, 1H),5.66 (br s, 1H), 3.86 (s, 3H); ¹³C NMR (125 MHz, CDCl₃): 6 191.8, 166.9,161.1, 148.4, 143.3, 138.1, 125.7, 120.7, 119.3, 113.6, 110.7, 108.8,71.7, 54.1; HRMS calc'd for C₁₄H₁₂NO₄[M+H]⁺258.0761, found 258.0764.

(Method A, with following modification: after addition of diazoazide 1aby syringe pump, reaction mixture was heated to reflux and stirred atthat temperature until consumption of 1a was observed) Isolated as ayellow oil in 41% yield; R_(f)=0.42 (7:3 hexanes:EtOAc); IR (cast film)3360, 3071, 2952, 1747, 1709, 1616, 1486, 1231, 754 cm⁻¹; ¹H NMR (500MHz, CDCl₃): δ 7.62 (ddd, J=7.2, 1.4, 0.7 Hz, 1H), 7.54 (ddd, J=8.4,7.2, 1.4 Hz, 1H), 7.49 (dd, J=3.7, 1.3 Hz, 1H), 7.24 (dd, J=5.1, 1.3 Hz,1H), 7.07 (d, J=8.3 Hz, 1H), 7.03 (dd, J=5.1, 3.7 Hz, 1H), 6.95 (app td,J=7.9, 0.7 Hz, 1H), 5.79 (br s, 1H), 3.85 (s, 3H); ¹³C NMR (125 MHz,CDCl₃): δ 192.2, 167.4, 160.9, 138.8, 137.9, 127.6, 125.9, 125.7, 125.5,121.1, 119.0, 113.7, 73.4, 54.1; HRMS calc'd forC₁₄H₁₂NSO₃[M+H]⁺274.0532, found 274.0536.

(Method A) Isolated as yellow crystals in 86% yield; m.p.=192-193° C.;R_(f)=0.16 (yellow spot, 7:3 hexanes:EtOAc); IR(cast film) 3371, 3057,2952, 1739, 1702, 1608, 1459, 1238, 745 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ8.40 (br s, 1H), 7.58-7.55 (m, 2H), 7.37-7.31 (m, 3H), 7.18 (ddd, J=7.9,7.0, 1.2 Hz, 1H), 7.10 (ddd, J=8.1, 7.1, 1.0 Hz, 1H), 6.89 (app t, J=7.5Hz, 1H), 5.53 (br s, 1H), 3.79 (s, 3H), 2.30 (s, 3H); ¹³C NMR (125 MHz,CDCl₃) δ 195.2, 169.2, 160.3, 138.0, 136.6, 125.5, 123.7, 122.8 (2×),122.7, 120.6, 120.4, 119.5 (2×), 111.8, 111.7, 72.6, 53.8, 15.8; HRMScalc'd for C₁₉H₁₇N₂O_(3 [)M+H]⁺321.1234, found: 321.1233.

(Method A) Isolated as yellow crystals in 84% yield (using MeOH as therecrystallization solvent); m.p.=170-171° C.; R_(f)=0.35 (yellow spot,7:3 hexanes:EtOAc); IR(cast film) 3359, 3055, 2950, 1746, 1705, 1608,1460, 1241, 743 cm⁻¹; ¹H NMR (500 MHz, CDCl₃) δ 7.61 (2 overlapping appt, J=8.2 Hz, 2H), 7.39-7.26 (m, 4H), 7.15 (app t, J=7.9 Hz, 1H), 6.91(app t, J=7.3 Hz, 1H), 5.58 (br s, 1H), 3.84 (s, 3H), 3.79 (s, 3H), 2.33(s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ 195.2, 169.2, 160.2, 137.9, 137.4,128.1, 126.1, 122.8, 122.7, 122.2, 120.5, 119.9, 119.5, 119.5, 110.0,109.8, 72.5, 53.8, 32.9, 15.8; HRMS calc'd for C₂₀H₁₉N₂O₃[M+H]⁺335.1390, found: 335.1388.

(Method A) Isolated as a yellow powder in 94% yield (using methanol asrecrystallization solvent): m.p.=184-186° C.; R_(f)=0.16 (7:3hexanes:EtOAc); IR (cast film) 3349, 3015, 2942, 1748, 1712, 1623, 1451,1239, 731 cm⁻¹; ¹H NMR (500 MHz, CDCl₃) δ 7.61 (d, J=7.8 Hz, 1H), 7.60(s, 1H), 7.28-7.09 (m, 10H), 6.48 (br s, 1H), 5.28 (s, 2H), 3.92 (s,3H), 3.87 (s, 3H), 3.82 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ 192.7,169.4, 158.9 (2×), 145.2, 136.9 (2×), 128.7, 127.6 (2×), 126.8, 126.4,122.3, 120.1, 119.5, 111.5, 110.8, 110.3, 104.5, 95.8, 73.0, 56.3, 56.2,53.7, 50.3; HRMS calc'd for C₂₇H₂₅N₂O₃ [M+H]⁺457.1685, found: 457.1683.

(Method A) Isolated as a yellow powder in 89% yield: m.p.=236-238° C.;R_(f)=0.19 (yellow spot, 7:3 hexanes:EtOAc); IR (cast film) 3364, 3052,2952, 1746, 1711, 1610, 1242, 741 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 8.21(br s, 1H), 7.61 (d, J=8.3 Hz, 1H), 7.55 (d, J=8.1 Hz, 1H), 7.40-7.37(m, 2H), 7.22 (app t, J=7.7 Hz, 1H), 7.12 (app t, J=8.1 Hz, 1H), 7.00(d, J=1.1 Hz, 1H), 6.90 (dd, J=8.3, 1.7 Hz, 1H), 5.77 (br s, 1H), 3.81(s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ 193.2, 168.6, 161.2, 144.5, 136.5,126.5, 125.3, 123.5, 122.9 121.2, 120.6, 119.4, 118.3, 113.4, 111.7,111.3, 72.8, 53.9; HRMS calc'd for C₁₈H₁₃ClN₂O₃Na [M+Na]⁺363.0507,found: 363.0508; Elemental analysis calc'd for C₁₈H₁₃ClN₂O₃: 63.45% C,3.85% H, 8.22% N; found, 63.35% C, 3.87% H, 8.13% N.

(Method A) Isolated as bright yellow crystals in 76% yield (usingmethanol as recrystallization solvent): m.p.=194-195° C.; R_(f)=0.35(7:3 hexanes:EtOAc); IR (cast film) 3364, 3052, 2952, 1746, 1711, 1610,1242, 741 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 7.61 (d, J=8.0 Hz, 1H), 7.52(ddd, J=8.0, 1.8, 1.0 Hz, 1H), 7.31 (ddd, J=8.3, 1.8, 1.1 Hz, 1H),7.26-7.22 (m, 2H), 7.10 (ddd, J=8.1, 7.0, 1.1 Hz, 1H), 6.99 (dd, J=1.7,0.5 Hz, 1H), 6.89 (dd, J=8.3, 1.7 Hz, 1H) 5.80 (br s, 1H), 3.81 (s, 3H),3.75 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ 193.3, 168.6, 161.1, 144.5,137.3, 128.0, 126.4, 125.8, 122.3, 121.1, 120.1, 119.3, 118.1, 113.3,109.8, 109.3, 72.7, 53.9, 32.9; HRMS calc'd for C₁₉H₁₆ ³⁵ClN₂O₃[M+H]⁺355.0844, found: 355.0846.

(Method A) Isolated as bright yellow crystals in 90% yield (80% yieldfrom direct recrystallization of crude and using methanol asrecrystallization solvent): m.p.=174-175° C.; R_(f)=0.42 (yellow spot,7:3 hexanes:EtOAc); IR (cast film) 3364, 3052, 2952, 1746, 1711, 1610,1242, 741 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 7.62 (app t, J=8.3 Hz, 2H),7.40 (s, 1H), 7.31-7.26 (m, 4H), 7.20 (app td, J=7.0, 0.9 Hz, 1H),7.14-7.11 (m, 3H), 6.97 (d, J=1.7 Hz, 1H), 6.89 (dd, J=8.3, 1.7 Hz, 1H)5.96 (br s, 1H), 5.26 (s, 2H), 3.81 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ193.3, 168.6, 161.1, 144.4, 136.9, 136.8 128.8, 127.7, 127.6, 126.8,126.4, 126.1, 122.5, 120.9, 120.2, 119.7, 118.0, 113.2, 110.4, 110.0,72.8, 53.8, 50.3; HRMS calc'd for C25H19³⁵ClN₂NaO₃ [M+Na]⁺453.0976,found: 453.0984.

(Method A; Note: due to concerns about potential hazards associated withstarting material, this reaction was carried out on 20 mg scale. As aresult, only partial characterization was obtained.) Light yellow solidin ca. 14% yield (corrected for impurity from EtOAc and water present):R_(f)=0.24 (yellow spot, 7:3 hexanes:EtOAc); IR (cast film) 3324, 3048,2956, 1738, 1714, 1610, 1251, 731 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 8.38(dd, J=8.2, 1.2 Hz, 1H), 8.01 (s, 1H), 8.00-7.98 (m, 2H), 7.56 (dd,J=8.1, 1.0 Hz, 1H), 7.38 (br s, 1H), 7.29-7.12 (m, 5H), 6.95 (dd, J=8.2,7.3 Hz, 1H), 5.26 (s, 2H), 3.83 (s, 3H); LC-MS calc'd for C₂₅H₁₉N₃O₅[M+H]⁺442.1, found: 442.1. (Due to small scale, no ¹³C NMR or HRMS datawere obtained.)

(Method A) Isolated as an orange oil in 96% yield: R_(f)=0.47 (orangespot, 7:3 hexanes:EtOAc); IR(cast film) 3359, 3055, 2950, 1746, 1705,1608, 1460, 1241, 743 cm⁻¹; ¹H NMR (500 MHz, CDCl₃) δ 8.29 (s, 1H), 7.84(d, J=8.3 Hz, 1H), 7.67 (d, J=8.4 Hz, 1H), 7.64 (d, J=8.1 Hz, 1H), 7.48(ddd, J=8.1, 6.8, 1.1 Hz, 1H), 7.42 (s, 1H), 7.29-7.23 (m, 6H), 7.17(app t, J=8.1 Hz, 1H), 7.11 (dd, J=8.0, 1.5 Hz, 2H), 7.08 (app td,J=8.1, 7.2 Hz, 1H), 5.76 (br s, 1H), 5.27 (s, 2H), 3.81 (s, 3H); ¹³C NMR(125 MHz, CDCl₃) δ 195.7, 169.3, 153.7, 139.9, 137.1, 136.9, 130.8,129.6, 128.8, 128.6, 127.7, 127.6, 127.2, 126.9, 126.7, 126.2, 123.7,122.4, 121.8, 120.2, 120.1, 110.8, 110.3, 107.0, 72.7, 53.7, 50.4; HRMScalc'd for C₂₉H₂₂N₂O₃Na [M+Na]⁺469.1523, found: 447.1530.

(Method A) Isolated as a yellow powder in 81% yield: m.p.=158-159° C.;R_(f)=0.19 (yellow spot, 7:3 hexanes:EtOAc); IR (cast film) 3368, 3055,2919, 1732, 1711, 1635, 1491, 1225, 757 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ8.36 (br s, 1H), 7.69 (ddd, J=7.8, 1.3, 0.7 Hz, 1H), 7.57 (d, J=8.1 Hz,1H), 7.52 (ddd, J=8.4, 7.1, 1.4 Hz, 1H), 7.32 (d, J=1.3 Hz, 1H), 7.30(app t, J=1.0 Hz, 1H) 7.17 (ddd, J=8.3, 7.1, 1.3 Hz, 1H), 7.08 (ddd,J=8.2, 7.1, 1.2 Hz, 1H), 6.98 (dt, J=8.3, 0.7 Hz, 1H), 6.93 (ddd, J=7.9,7.1, 0.9 Hz, 1H), 5.84 (tdd, J=5.6, 10.5, 17.2 Hz, 1H), 5.83 (br s, 1H),5.23 (tdd, J=1.5, 1.5, 17.2 Hz, 1H), 5.16 (tdd, J=1.3, 1.3, 10.5 Hz,1H), 4.71-4.67 (m, 2H); ¹³C NMR (125 MHz, CDCl₃,): δ 194.8, 168.2,161.1, 137.9, 136.5, 131.1, 125.4 (2×), 123.8, 122.6, 120.3 (2×), 119.8,119.6, 119.2, 113.5, 111.7, 111.3, 72.6, 67.2; HRMS calc'd forC₂₀H₁₇N₂O₃ [M+H]⁺333.1234, found: 333.1232.

(Method A) Isolated as yellow crystals in 83% yield (using methanol asthe recrystallization solvent): m.p.=148-150° C.; R_(f)=0.36 (yellowspot, 7:3 hexanes:EtOAc); IR (cast film) 3371, 3051, 2919, 1742, 1703,1615, 1485, 1225, 743 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 7.72 (d, J=7.8Hz, 1H), 7.63 (d, J=8.1 Hz, 1H), 7.52 (ddd, J=8.3, 7.1, 1.3 Hz, 1H),7.32-7.30 (m, 2H), 7.26 (ddd, J=8.2, 7.0, 1.1 Hz, 1H), 7.12 (ddd, J=8.0,7.0, 1.1 Hz, 1H), 6.99 (d, J=8.2 Hz, 1H), 6.94 (app t, J=7.8 Hz, 1H),5.88 (ddt, J=17.2, 10.5, 5.6 Hz, 1H), 5.83 (br s, 1H), 5.29 (ddt,J=17.2, 1.5, 1.5 Hz, 1H), 5.22 (ddt, J=10.4, 1.2, 1.2 Hz, 1H), 4.75-4.71(m, 2H), 3.73 (s, 3H); ¹³C NMR (125 MHz, CDCl₃,): δ 194.7, 168.3, 161.0,137.8, 137.4, 131.2, 128.1, 126.0, 125.4, 122.2, 120.2, 119.9(2×),119.8, 119.1, 113.5, 109.8, 109.7, 72.5, 67.1, 32.9; HRMS calc'd forC₂₁H₁₉N₂O₃ [M+H]⁺347.1390, found: 347.1393.

(Method A) Isolated as a yellow powder in 73% yield: m.p.=193-195° C.;R_(f)=0.21 (yellow spot, 7:3 hexanes:EtOAc); IR (cast film) 3351, 3011,2915, 1738, 1712, 1635, 1465, 1233, 758 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ8.25 (br s, 1H), 7.70 (d, J=8.0 Hz, 1H), 7.60 (dd, J=8.1, 0.9 Hz, 1H),7.54 (ddd, J=8.3, 7.2, 1.4 Hz, 1H), 7.43 (d, J=2.7 Hz, 1H), 7.37 (appdt, J=8.2, 0.8 Hz, 1H), 7.25 (dd, J=13.9, 6.2 Hz, 1H), 7.20 (ddd, J=8.2,7.2, 1.1 Hz, 1H), 7.10 (ddd, J=8.2, 7.2, 1.0 Hz, 1H), 7.01 (d, J=8.3 Hz,1H), 6.94 (app t, J=7.8 Hz, 1H), 5.68 (br s, 1H), 4.99 (dd, J=13.9, 2.0Hz, 1H), 4.66 (dd, J=6.1, 2.0 Hz, 1H); ¹³C NMR (125 MHz, CDCl₃): δ194.0, 165.8, 160.9, 141.3, 138.0, 136.5, 125.5, 125.3, 123.7, 122.8,120.5 (2×), 119.7, 119.6, 113.5, 111.6, 111.0, 100.0, 72.1; HRMS calc'dfor C₁₉H₁₄N₂O₃Na [M+Na]⁺318.1004, found: 318.1007.

(Method A) Isolated as bright yellow crystals in 71% yield:m.p.=195-196° C.; R_(f)=0.20 (yellow spot, 7:3 hexanes:EtOAc); IR (castfilm) 3364, 3052, 2952, 1711, 1610, 1242, 741 cm⁻¹; ¹H NMR (500 MHz,CDCl₃): δ 8.16 (m, 2H), 7.66 (d, J=8.5 Hz, 1H), 7.51 (ddd, J=8.4, 7.1,1.4 Hz, 1H), 7.46-7.38 (m, 2H), 7.31-7.19 (m, 5H), 7.06 (ddd, J=8.1,7.0, 1.0 Hz, 1H), 7.01 (d, J=8.3 Hz, 1H), 6.92 (app t, J=7.8 Hz, 1H),6.26 (br s, 1H), 3.77 (s, 3H); ¹³C NMR (125 MHz, CDCl₃) δ 195.2, 193.6,161.1, 137.8, 137.4, 134.2, 133.2, 131.3, 127.9, 127.6, 126.1, 125.2,122.4, 120.5, 120.3, 120.1, 119.3, 114.0, 112.0, 109.8, 79.0, 33.0;LC-MS calc'd for C₂₄H₁₉N₂O₂ [M+H]⁺366.1, found: 366.1.

(Method A) Isolated as bright yellow powder in 81% yield, inseparablemixture (HPLC, ca. 1.3:1 ratio of 2xa:2xb, characterized as mixture ofdiastereomers): R_(f)=0.21 (yellow spot, 7:3 hexanes:EtOAc); IR (castfilm) 3362, 3051, 2955, 1705, 1618, 1242, 739 cm⁻¹; ¹H NMR (500 MHz,CDCl₃): 8 (major isomer 2xa) 8.26 (br s, 1H), 7.69 (dddd, J=7.8, 1.4,0.7, 0.7 Hz, 1H), 7.59-7.58 (m, 1H), 7.51 (ddd, J=8.3, 7.2, 1.4, 1H),7.50 (ddd, J=8.3, 7.2, 1.4, 1H), 7.37 (d, J=2.7 Hz, 1H), 7.34 (ddd,J=8.2, 0.9, 0.9 Hz, 1H), 7.09 (ddd, J=8.1, 7.1, 1.1 Hz, 1H), 6.99 (dd,J=0.8, 0.8 Hz, 1H), 6.93 (ddd, J=7.1, 0.9, 0.9 Hz, 1H), 5.65 (br s, 1H)4.77 (ddd, J=10.9, 10.9, 4.3 Hz, 1H), 0.84 (d, J=6.5 Hz, 3H), 0.82 (d,J=7.0 Hz, 3H), 0.64 (d, J=6.9 Hz, 3H), 8 (minor isomer 2xb) 8.24 (br s,1H), 7.70 (dddd, J=7.8, 1.4, 0.6, 0.6 Hz, 1H), 7.61-7.60 (m, 1H), 7.38(d, J=2.7 Hz, 1H), 7.33 (ddd, J=8.1, 0.9, 0.9 Hz, 1H), 7.06 (ddd, J=8.1,7.1, 1.0 Hz, 1H), 7.00 (dd, J=0.7, 0.7 Hz, 1H), 6.92 (ddd, J=7.1, 0.9,0.9 Hz, 1H), 5.76 (br s, 1H), 4.72 (ddd, J=11.0, 11.0, 4.4 Hz, 1H), 0.86(d, J=6.5 Hz, 3H), 0.51 (d, J=7.1 Hz, 3H), 0.43 (d, J=6.9 Hz, 3H) (Note:some protons could not be properly assigned due to extensive spectraloverlap); ¹³C NMR (125 MHz, CDCl₃) δ 194.8, 194.6, 168.0 (2×), 161.2,161.0, 137.7, 137.6, 136.6, 136.5, 125.7, 125.6, 125.4, 125.3, 123.7,123.4, 122.6 (2×), 120.3, 120.2 (2×), 120.1 (3×), 120.0, 119.6, 113.7,113.5, 111.9, 111.8, 111.5 (2×), 77.5, 77.4, 72.8, 72.7, 46.8, 46.7,40.3, 40.2, 34.1 (2×), 31.5, 25.8, 25.5, 23.2, 23.0, 22.0, 20.8, 20.4,15.9, 15.7 (Note: 2 aliphatic carbon resonances were not detected due toextensive spectral overlap); HRMS calc'd for C₂₇H₃₁N₂O₃ [M+H]⁺431.2329,found: 431.2332.

(Method A) Isolated as bright yellow powder in 79% yield, inseparablemixture (HPLC, ca. 2.3:1 ratio of 2ya:2yb, characterized as mixture ofdiastereomers): R_(f)=0.33 (yellow spot, 7:3 hexanes:EtOAc); IR (castfilm) 3362, 3051, 2955, 1704, 1618, 1242, 740 cm⁻¹; ¹H NMR (500 MHz,CDCl₃): 8 (major isomer 2ya) 7.58 (ddd, J=8.0, 1.0, 1.0 Hz, 1H), 7.51(ddd, J=8.3, 7.1, 1.3 Hz, 1H), 7.06 (ddd, J=8.1, 7.1, 1.1 Hz), 5.65 (brs, 1H), 4.77 (ddd, J=10.8, 10.8, 4.3 Hz, 1H), 3.75 (s, 3H), 1.85 (sepd,J=7.1, 2.9 Hz, 1H), 0.87 (d, J=6.6 Hz, 3H), 0.83 (d, J=7.0 Hz, 3H), 0.64(d, J=7.0 Hz, 3H), 8 (minor isomer 2yb) 7.59 (ddd, J=8.0, 0.9, 0.9 Hz,1H), 7.50 (ddd, J=8.4, 7.2, 1.4, 1H), 7.09 (ddd, J=8.1, 7.1, 1.0 Hz,1H), 5.76 (br s, 1H), 4.73 (ddd, J=10.9, 10.9, 4.4 Hz, 1H), 3.74 (s,3H), 1.19 (sepd, J=7.0, 2.9 Hz), 0.86 (d, J=6.6 Hz, 3H), 0.52 (d, J=7.0Hz, 3H), 0.44 (d, J=6.9 Hz, 3H) (Note: some protons could not beproperly assigned due to extensive spectral overlap); ¹³C NMR (125 MHz,CDCl₃) δ 194.9, 194.7, 168.1, 168.0, 161.2, 160.9, 137.7, 137.6, 137.3(2×), 128.1, 127.9, 126.2, 126.0, 125.4, 125.3, 122.1 (2×), 120.2 (2×),120.0 (3×), 119.7 (3×), 113.7, 113.5, 110.1, 110.0, 109.6, 109.5, 77.4,77.3, 72.8, 72.7, 46.7, 46.6, 40.3, 40.2, 34.1 (2×), 32.9 (2×), 31.4,25.7, 25.4, 23.1, 23.0, 21.9, 20.8, 20.4, 15.9, 15.7 (Note: two carbonresonances could not be found due to extensive overlap); HRMS calc'd forC₂₈H₃₂N₂O₃ [M+H]⁺445.2486, found: 445.2492.

Compounds 2za and 2zb:

(Method A) Isolated in 92% combined yield (2.7:1 ratio of 2za:2zb).

Major diastereomer 2za (isolated as green needles from partialseparation of mixture): R_(f)=0.42 (yellow spot, 7:3 hexanes:EtOAc);[α]_(D) ²⁰: +23.76 (c=1.01, DCM); IR (cast film) cm⁻¹; ¹H NMR (500 MHz,CDCl₃): δ 7.68 (d, J=7.8 Hz, 1H), 7.62 (d, J=8.8 Hz, 1H), 7.52 (ddd,J=8.3, 7.2, 1.3, 1H), 7.39 (s, 1H), 7.30-7.22 (m, 4H), 7.14 (ddd, J=8.2,7.1, 1.1, 1H), 7.13-7.11 (m, 2H), 7.06 (ddd, J=8.1, 7.1, 1.0, 1H), 7.01(d, J=8.2 Hz, 1H), 6.92 (app t, J=7.8 Hz, 1H), 5.66 (br s, 1H), 5.28(app br s, 2H), 4.75 (ddd, J=11.0, 11.0, 4.4 Hz, 1H), 1.91-1.88 (m, 1H),1.81 (sepd, J=7.0, 2.9 Hz, 1H), 1.66-1.61 (m, 2H), 1.45-1.39 (m, 2H),1.03-0.96 (m, 1H), 0.88 (app td, J=12.2, 11.0 Hz, 1H) 0.87-0.70 (m, 1H),0.84 (d, J=6.6 Hz, 3H), 0.81 (d, J=7.0 Hz, 3H), 0.62 (d, J=7.0 Hz, 3H);¹³C NMR (125 MHz, CDCl₃) δ 194.8, 167.9, 161.0, 137.6, 137.1, 137.0,128.8, 127.7, 127.6, 127.0, 126.3, 125.4, 122.3, 120.3, 120.2, 120.1,120.0, 113.5, 110.7, 110.1, 77.4, 72.8, 50.3, 46.8, 40.2, 34.1, 31.4,25.8, 23.2, 22.0, 20.7, 15.9; HRMS calc'd for C₃₄H₃₇N₂O₃ [M+H]⁺521.2799,found: 521.2810.

Minor diastereomer 2zb (partial assignment based on deduction, usingspectra of mixture of diastereomers and spectra of major diastereomer;multiplicity of some peaks could not be properly assigned due tosubstantial overlap): ¹H NMR (500 MHz, CDCl₃): δ 7.68 (d, J=7.8 Hz, 1H),7.65 (d, J=7.6 Hz, 1H), 7.51 (ddd, J=8.4, 7.2, 1.3 Hz, 1H), 7.41 (s,1H), 7.30-7.22 (m, 4H), 7.15 (app t, J=7.2 Hz, 1H), 7.12-7.11 (m, 3H),7.02 (d, J=8.16 Hz, 1H), 6.92 (app t, J=7.8 Hz, 1H), 5.80 (br s, 1H),5.28 (app br s, 2H), 4.72 (ddd, J=11.0, 10.9, 4.4 Hz, 1H), 1.95-1.92 (m,1H), 1.66-1.55 (m, 2H), 1.47-1.33 (m, 2H), 1.15 (sepd, J=6.9, 2.9 Hz,1H), 0.87 (d, J=6.6 Hz, 3H), 0.48 (d, J=7.0 Hz, 3H), 0.40 (d, J=6.9 Hz,3H) (NB.: three protons in aliphatic region could not be properlyassigned due to extensive spectral overlap); ¹³C NMR (125 MHz, CDCl₃) δ194.5, 168.1, 161.2, 137.7, 137.2, 136.9, 128.8, 127.7, 127.4, 126.7,126.5, 125.4, 122.3, 120.3, 120.2, 120.0, 113.7, 110.9, 110.1, 77.4,72.7, 50.3, 46.7, 40.3, 34.1, 31.4, 25.5, 23.0, 22.0, 20.4, 15.7 (NB.:one resonance ¹³C was missing and could not be properly assigned due toextensive spectral overlap).

(Method A) Isolated as a bright yellow powder in 84% yield: m.p.=120° C.(dec.); R_(f)=0.32 (3:7, EtOAc:hexanes); IR(cast film) 3345, 3015, 2960,1744, 1712, 1617, 1465, 1234, 733 cm⁻¹ ¹H NMR (500 MHz, CDCl₃): δ 8.41(s, 1H), 7.50 (d, J=8.3 Hz, 1H), 7.40-7.28 (m, 6H), 7.21-7.16 (m, 2H),7.05 (app. t, J=7.7 Hz, 1H), 6.91 (d, J=1.5 Hz, 1H), 6.89 (dd, J=8.3,1.7 Hz, 1H), 5.73 (s, 1H), 3.22 (s, 3H); ¹³C NMR (125 MHz, CDCl₃): δ193.7, 168.5, 160.8, 144.3, 138.0, 135.4, 132.4, 129.5, 128.8, 128.3,126.7, 126.1, 122.6, 121.0, 120.6, 119.4, 118.4, 113.0, 111.3, 107.5,73.6, 53.2; HRMS calc'd for C₂₄H₁₇ ³⁵ClN₂NaO₃[M+Na]⁺439.0822, found439.0822.

(Method A) Isolated as a bright yellow powder in 88% yield: m.p.=120° C.(dec.); R_(f)=0.17 (3:7, EtOAc:hexanes); IR (cast film) 3338, 3027,2953, 1741, 1708, 1624, 1461, 1237, 747 cm⁻¹¹H NMR (500 MHz, CDCl₃): δ8.20 (s, 1H), 7.52 (d, J=8.2 Hz, 1H), 7.33-7.30 (m, 3H), 7.19-7.15 (m,2H), 7.03 (ddd, J=8.2, 7.2, 1.1 Hz, 1H), 6.94 (dd, J=1.7, 0.6 Hz, 1H),6.89-6.85 (m, 3H), 5.63 (s, 1H), 3.82 (s, 3H), 3.31 (s, 3H); ¹³C NMR(125 MHz, CDCl₃): δ 193.7, 168.6, 160.8, 160.1, 144.3, 137.9, 135.3,130.9, 126.8, 126.2, 124.7, 122.6, 121.0, 120.6, 119.4, 118.6, 113.8,113.1, 111.2, 107.5, 73.6, 55.4; 53.4; HRMS calc'd for C₂₅H₂₀³⁵ClN₂O₄[M+H]⁺447.1106, found 447.1105.

(Method A) Isolated as a bright yellow powder in 67% yield: m.p.=135° C.(dec.), R_(f)=0.21 (3:7, EtOAc:hexanes); IR(cast film) 3336, 3021, 2945,1739, 1712, 1615, 1471, 1239, 749 cm⁻¹ ¹H NMR (500 MHz, CDCl₃): δ 8.15(s, 1H), 7.51 (dd, J=8.2, 0.6 Hz, 1H), 7.43-7.40 (m, 2H), 7.36 (d, J=8.0Hz, 1H), 7.22-7.18 (m, 2H), 7.07-7.04 (m, 3H), 6.98 (dd, J=1.7, 0.5 Hz,1H), 6.90 (dd, J=8.2, 1.7 Hz, 1H), 5.62 (s, 1H), 3.35 (s, 3H); ¹³C NMR(125 MHz, CDCl₃): δ 193.4, 168.5, 163.1 (d, J=249.5 Hz), 160.7, 144.5,136.8, 135.4, 131.6 (d, J=8.3 Hz), 128.5, 126.7, 126.2, 123.0, 121.3,120.9, 119.4, 118.6, 115.5 (d, J=21.7 Hz), 113.1, 111.2, 108.2, 73.4,53.5; ¹⁹F NMR (469 MHz, CDCl₃): δ-111.7 (br s); HRMS calc'd for C₂₄H₁₇³⁵ClFN₂O₃ [M+H]⁺435.0904, found 435.0906.

(Method A) Isolated as a bright yellow solid in 51% yield: m.p.=148° C.(dec.), R_(f)=0.30 (3:7, EtOAc:hexanes); IR(cast film) 3344, 3039, 2957,1729, 1712, 1659, 1464, 1239, 731 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 8.17(br s, 1H), 7.48 (d, J=8.2 Hz, 1H), 7.47 (dd, J=7.0, 2.2 Hz, 1H), 7.37(d, J=10.3 Hz, 1H), 7.32 (ddd, J=6.8, 4.6, 2.2 Hz, 1H), 7.27-7.21 (m,2H), 7.13-7.07 (m, 2H), 7.01 (d, J=1.6 Hz, 1H), 6.91 (dd, J=8.3, 1.7 Hz,1H), 5.66 (s, 1H), 3.48 (s, 3H); ¹³C NMR (125 MHz, CDCl₃): 6 193.2,168.6, 163.0 (d, J=249.5 Hz), 160.4, 157.4, 144.6, 135.5, 135.2, 132.0,129.5 (d, J=19.9 Hz), 129.4, 126.8, 126.1, 123.3, 121.5, 121.0, 119.3,118.7, 116.6 (d, J=25.1 Hz), 113.2, 111.4, 108.9, 73.2, 53.6; ¹⁹F NMR(469 MHz, CDCl₃): δ-114.2 (br s); HRMS calc'd for C₂₄H₁₅Cl₂FN₂O₃Na[M+Na]⁺491.0336, found 491.0334.

(Method A) Isolated as a bright yellow powder in 74% yield; m.p.=120° C.(dec.); R_(f)=0.32 (3:7, EtOAc:hexanes); IR(cast film) 3342, 3025, 2950,1741, 1709, 1618, 1460, 1231, 733 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 8.32(s, 1H), 7.42 (d, J=8.3 Hz, 1H), 7.26-7.39 (m, 6H), 7.14-7.19 (m, 2H),7.10 (d,J=1.5 Hz, 1H), 7.01-7.05 (m, 2H), 5.67 (s, 1H), 3.21 (s, 3H);¹³C NMR (125 MHz, CDCl₃): δ 193.9, 168.4, 160.8, 138.0, 135.4, 133.3,132.4, 129.5, 128.8, 128.4, 126.7, 126.2, 123.8 122.7, 120.6, 119.4,118.8, 116.1, 111.3, 107.6, 73.5, 53.2. HRMS calc'd forC₂₄H₁₈BrN₂O₃[M+H]⁺461.0495, found 461.0501.

(Method A) Isolated as a bright yellow solid in 76% yield; m.p.=120° C.(dec.); R_(f)=0.32 (3:7, EtOAc:hexanes); IR(cast film) 3347, 3033, 2956,1731, 1713, 1638, 1465, 1236, 713 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 8.12(br s, 1H), 7.46 (d, J=8.3 Hz, 1H), 7.26-7.12 (m, 3H), 7.19-7.14 (m,3H), 7.05-7.03 (m, 2H), 7.02-6.88 (m, 2H), 5.59 (s, 1H), 3.83 (s, 3H),3.32 (s, 3H); ¹³C NMR (125 MHz, CDCl₃): δ 193.9, 168.6, 160.8, 160.1,138.0, 135.4, 133.3, 130.9, 126.8, 126.2, 124.7, 123.8, 121.0, 120.6,119.4, 118.7, 116.1, 113.8, 111.2, 107.6, 73.5, 55.4, 53.4; FIRMS calc'dfor C₂₅H₂₀ ⁷⁹BrN₂O₄ [M+H]⁺491.0601, found 491.0605.

(Method A) Isolated as a bright yellow solid in 52% yield: m.p.=120° C.(dec.); R_(f)=0.32 (3:7, EtOAc:hexanes); IR(cast film) 3339, 3035, 2954,1728, 1718, 1648, 1464, 1229, 728 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 8.17(br s, 1H), 7.46 (d, J=8.3 Hz, 1H), 7.26-7.12 (m, 3H), 7.19-7.14 (m,3H), 7.05-7.03 (m, 2H), 7.02-6.88 (m, 2H), 5.59 (s, 1H), 3.32 (s, 3H);¹³C NMR (125 MHz, CDCl₃): δ 193.7, 168.4, 163.1 (d, J=249.5 Hz), 160.7,136.8, 135.4, 133.4, 131.6 (d, J=8.3 Hz), 128.5, 126.7, 126.2, 124.0,123.0, 120.9, 119.4, 119.0, 116.2, 115.5 (d, J=21.6 Hz), 111.2, 108.1,73.3, 53.5;¹⁹F NMR (469 MHz, CDCl₃): δ-111.7 (br s); HRMS calc'd forC₂₄H₁₇ ⁷⁹BrFN₂O₃ [M+H]479.0402, found 479.0404.

(Method A) Isolated as a bright yellow solid in 38% yield: m.p.=120° C.(dec.); R_(f)=0.30 (3:7, EtOAc:hexanes); IR(cast film) 3341, 3037, 2951,1724, 1716, 1651, 1465, 1234, 737 cm⁻¹; ¹H NMR (500 MHz, CDCl₃): δ 8.21(br s, 1H), 7.46 (dd, J=7.0, 2.2 Hz, 1H), 7.40 (d, J=8.2 Hz, 1H), 7.35(d, J=8.2 Hz, 1H), 7.30 (ddd, J=6.8, 4.5, 2.2 Hz, 1H), 7.24-7.20 (m,2H), 7.19 (dd, J=1.5, 0.4 Hz, 1H), 7.11-7.06 (m, 3H), 5.66 (s, 1H), 3.48(s, 3H); ¹³C NMR (125 MHz, CDCl₃): δ 193.2, 168.6, 163.0 (d, J=249.5Hz), 160.4, 151.1, 142.0, 133.3, 133.2, 132.0, 129.5, 129.4 (d, J=19.9Hz), 126.8, 126.1, 124.5, 123.2, 121.0, 119.3, 119.0, 116.6 (d, J=25.1Hz), 116.3, 111.4, 108.9, 73.2, 53.6; ¹⁹F NMR (469 MHz, CDCl₃): δ-114.2(br s); HRMS calc'd for C₂₄H₁₆ ⁷⁹Br³⁵ClFN₂O₃[M+H]⁺513.0012, found513.0015.

Virology Procedures

Cells and virus. Hep-2 cells were grown in Opti-MEM media supplementedwith 2% fetal bovine serum (FBS), 1HAEo-cells were grown in MEM mediasupplemented with 10% FBS, and Hela cells grown in DMEM supplementedwith 10% FBS. Infections were conducted using human RSV strain A2 orRSV-A2-GFP strain described previously [Hallak, L. K.; Spillmann, D.;Collins, P. L.; Peeples, M. E. J. Virol. 2000, 74, 10508-10513]. A549cells and Vero cells were grown in DMEM supplemented with 10% FBS andused for experiments with ZIKV (Cambodia strain).

Structure activity relationship screens of antiviral activity.1HAEo-cells were seeded at 80% confluency and incubated overnight. InSAR1 cells were preincubated with compounds for one hour at 20 μM priorto infection, followed by dilution to 10 μM and infection withRSV-A2-GFP at an MOI of 1 for 2 hours. In SAR2 1HAEo-cells were infectedwith RSV-A2-GFP at an MOI of 0.5 for 2 hours without pre-incubation withcompounds. At 2 hours post infection, infectious media was removed fromwells to prevent carry over of infecting virus into progeny collections.Fresh media containing compounds at 10 μM was added for remainder of 48hour incubation. HeLa cells, used to titrate progeny virus, were platedat 80% confluency and incubated overnight. Progeny virus collected at 48hours was immediately transferred to HeLa cells in duplicate technicalreplicates without dilution. At 2 hours post infection media wasreplaced with fresh compound-free media. Infection was stopped at 20hours post infection, preventing cell to cell spread of virus, andinfected cells were identified via indirect immunofluorescence assay.

Progeny virus quantification via indirect immunofluorescence. HeLa cellswere fixed in 1:1 methanol:acetone, incubated with goat anti-RSVpolyclonal antibody (Meridian Life Science B65860G) for 1 hour at roomtemperature, and then incubated with chicken anti-goat polyclonalantibody conjugated to Alexafluor 647 (LifeTech A-21469). Finally, cellnuclei were stained with DAPI. Total cells (identified by DAPI staining)and infected cells were counted via the Operetta high content imagingsystem at 20x objective magnification.

MTT cell viability assay. 1HAEo-cells were grown in parallel withinfected and compound treated cells in SAR and dose responseexperiments. 0.3mg/mL of MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)) in PBS was added to wells and incubated for 1hour. Precipitate was dissolved in DMSO and absorbance was measured at570 nm.

Cell extract-based in vitro inhibition of viral transcription. Theprotocol utilized to examine in vitro viral transcription was firstdeveloped for virus vesicular stomatitis virus [Canter, D. M.; Jackson,R. L.; Perrault, J. Virology 1993, 194, 518-529], and adapted for RSV aspublished previously [Noton, S. L.; Nagendra, K.; Dunn, E. F.;Mawhorter, M. E.; Yu, Q.; Fearns, R. J. Virol. 2015, 89, 7786-7798].Briefly, HEp-2 cells were grown in 6 well plates overnight toapproximately 80% confluence and infected with RSV A2 at an MOI of 5 for1 hour before incubating overnight in fresh media. Immediately beforecell lysis, cells were incubated in 2 μg/mL actinomycin D to blockcellular transcription. Cells were lysed on ice via 1 minute treatmentwith lysolecithin, and cell extract was subsequently collected intranscription buffer containing 50 mM Tris-acetate at pH 8, 8 mM Mgacetate, 300 mM K acetate, 2 mM DTT, 1 mM spermidine, 10 mM creatinephosphatase, 1 μg/mL aprotinin, 16 U creatine phosphokinase, 1 mM eachof ATP, GTP, and CTP, 50 μM UTP, and 2 μg/mL actinomycin D. Cell debriswas removed via refrigerated centrifugation. In vitro transcriptionreaction was performed by combining soluble cell extract, additionaltranscription buffer, RNase Inhibitor, compound 28 diluted in DMSO, and10 μCi [α 32-P] UTP, incubated at 30° C. for 3 hours. RNA extraction wasperformed with Qiagen RNeasy kit as per manufacturer protocol to purifysamples, followed by hybridization with oligo(dT) to facilitate RNaseHdigestion of mRNA transcript poly(A) tails. Denaturing electrophoresisof samples was performed using 4% acrylamide containing 7 M urea gels.Gels were dried and autoradiography captured during 4 day exposure.Viral RNA products were quantified by densitometry analysis followingphosphorimaging (n=4).

Dose response experiments. 1HAEo-cells were infected as described,progeny virus collected, and tittered on HeLa cells in duplicate asdescribed in SAR 2. During initial infection in 1HAEo-cells infectiousmedia was replaced with media containing compounds at indicatedconcentrations at 2 hours post infection. Proportion of virus infectedcells were quantified via indirect immunofluorescence assay.

Mutant escape assay. 1HAEo-cells were infected with RSV-GFP-A2 at aninitial MOI of 0.1 and serial passaged over incubation periods of 48-72hours. Samples were collected during passaging and stored in liquidnitrogen for tittering via indirect immunofluorescence assay. Ongoinglow level viral infection during passaging was confirmed byidentification of green fluorescence from GFP produced by the RSV-GFP ininfected cells.

Zika Virus antiviral screen. Vero cells were pre-treated withbis(indole) compounds at 10 μM for 4 hours before infection with ZIKV atan MOI of 1. After 48 hour infection progeny ZIKV was collected, serialdiluted over 6 logs, and transferred onto fresh Vero cell monolayers andincubated for 4 days. Vero cell monolayers were then fixed with 10%formaldehyde and stained with crystal violet; viral infection wasquantified via plaque assay.

Results and Discussion

Conditions originally employed for the cascade process utilized 10 mol %Cu(hfacac)₂ and heating (toluene at reflux). Catalytic generation ofcopper metallocarbenes from diazoketone precursors is generally acceptedto require the Cu(I) oxidation state, necessitating in situ reduction ofthe starting Cu(II) salt by added reductant or a sacrificial quantity ofthe diazo substrate. Once tthe C-acylimine was formed, it was consideredthat nucleophilic trapping involved activation of the imine nitrogenatom by either Cu(I) or unreduced Cu(II). Using substrate 1a and indoleas the trap, only moderate yields of the desired adduct 2a were observedunder standard conditions, complicated by varying amounts of theregioisomer resulting from Friedel-Crafts trapping at C-2 (Table 1,entry 1). Attempts to improve selectivity by reducing reactiontemperature were not fruitful, providing only traces of 2a after 24 h,which was attributed to slow production of catalytically competent Cu(I)(entry 2). Cu(OTf).PhCH₃ in DCM at rt afforded 2a in only 12% yield,although 1a was consumed quickly (Table 1, entry 3). In contrast, use of10 mol % Cu(OTf)₂ required extended stirring in DCM at rt, butultimately provided 2a in 92% yield (Table 1, entry 4), and theseconditions were scalable (Table 1, entry 5). Induction time wasconsistent with a pre-activation step to generate CuOTf, but the highyield in this case (in contrast to entry 3) suggested a requirement foranother component besides Cu(I) to attain efficient production of indoleadduct 2a.

Species responsible for reduction of Cu(OTf)₂ was not clear. As notedabove, diazo compounds are known to play this role, but the presence ofexcess indole suggested an alternative possibility. Gaunt and co-workershave shown that direct C-3 arylation of indoles can be accomplishedusing catalytic Cu(OTf)₂, involving C-3 cupration of the indole by aCu(III) intermediate, ArCu(OTf)₂, which is formed via CuOTf insertion toan aryliodonium salt [Phipps, R. J.; Grimster, N. P.; Gaunt, M. J. J.Am. Chem. Soc. 2008, 130, 8172-8174]. In the present context, it wasconsidered that indole C-3 cupration by Cu(OTf)₂ could formorganocopper(II) complex 3, which could furnish CuOTf through hemolyticcleavage of the weak C—Cu bond (See FIG. 2). Alternatively, it wasconsidered that disproportionation of 3 with another molecule ofCu(OTf)₂ would afford the required CuOTf along with a Cu(III) complex.It was noted that 1a was recovered unconsumed after stirring for 72 h atrt in the presence of Cu(OTf)₂ in the absence of indole (Table 1, entry6), whereas 1a was rapidly consumed to give mostly uncharacterizableproducts when stirred at rt with CuOTf.PhCH₃. Thus, it was consideredthat Cu(I) may be necessary for consumption of the diazo substrate, andthat the diazo compound was not sufficient for reduction of Cu(II), atleast at rt. Copper(0) was ineffective at catalyzing the process (Table1, entry 7), and other solvents gave results inferior to those using DCM(Table 1, entries 8-10). Use of a lower reaction temperature (Table 1,entry 11) or addition of a bidentate bis(oxazoline) ligand (Table 1,entry 12) suppressed consumption of 1a.

One equivalent of the strong Bronsted acid TfOH was produced along witheach equivalent of CuOTf, and its presence appeared to be required forclean trapping by indole to furnish 2a. Thus, while treatment of 1a with10 mol % CuOTf.PhMe gave minor amounts of 2a despite completeconsumption of starting material (Table 1, entry 3), when 10 mol %Cu(OTf)₂ was pretreated with 0.2 equiv indole and stirred for 2 h (greensolution) then added to a solution of 1a and 1.8 equiv indole, 2a wasobtained in 83% yield. The exact nature of the Bronsted acid catalystresponsible for indole addition was unclear, but the indolylindolinetriflate salt 4 was considered a feasible candidate. This dimericproduct is readily formed from indole in the presence of Bronsted orLewis acid and various electrophilic reagents, and evidence for itsformation was observed during the indole/copper(II) redox process (seeExample 2). Overall, the cascade process was considered to involve adual catalytic cycle involving Cu(I)-catalyzed conversion of 1a to thecyclized indolen-3-one intermediate, followed by Bronsted acidactivation of the imine (and concomitant turnover of Cu(I)) forFriedel-Crafts alkylation of indole to afford 2a (see FIG. 2).

Direct involvement of Bronsted acid in the indole addition step is borneout by the observation of an enantiomeric excess of 36% when thereaction was carried out in the presence of (+)-camphorsulfonic acid(see FIG. 3). In this case, it was assumed that (+)-CSA competeseffectively with the indolinium triflate Bronsted acid to catalyzeindole trapping with asymmetric induction occurring via the chiralcounterion. The modest enantiomeric excess may arise from a competingracemic background process, or from weak asymmetric induction by thecamphorsulfonate.

To test the scope of the dual catalytic process, other indolederivatives with varying steric and electronic properties were subjectedto the optimal reaction conditions (see FIG. 4). Use of a simpleN-methyl or an N-benzyl protected indole as a trap did not appear tosignificantly affect the reaction rate, and adducts 2b and 2c wereproduced in excellent yields. The presence of a bulky substituent at C-2position of the indole did not appear to impede the C-acylimine trappingprocess, as exemplified by formation of 2d in high yield (93%) over thestandard reaction time. Consistent with the proposed electrophilicmetalation activation mechanism, 4-bromoindole was compatible with thereaction conditions and produced 2e in reasonable yield, albeit with alonger reaction time (>24 h) than when an unsubstituted indole was used.Electron-rich 5-methoxyindole produced 2f in good yield and in arelatively short reaction time. Other types of heteroaromatics such aspyrrole, thiophene, furan and benzofuran were amenable to the reactionconditions and afforded adducts 2h-k in moderate yields, althoughheating the reaction mixture to reflux was required to drive thereaction to completion. Deactivated N-acylindoles were found to beunreactive (e.g., no formation of 2g).

Effects of substitution on the diazoazide partner were also examined.Substitution with an electron donating methyl or methoxy group gavebetter yields of adducts 21-n (84-94%) than the electron-withdrawingnitro group (2o, 14% along with 68-76% recovered starting material). Thepresence of halogen substituent (chloro) meta to the azide or extendingthe aromatic system were tolerated, furnishing adducts 2p-s in goodyields. Allyl, vinyl, or menthyl esters adjacent to the diazo group weretolerated, as was phenyl ketone, affording 2t-2z in good to excellentyields.

With rapid access to a library of truncated isatasine A analoguesavailable, their potential antiviral activity against RSV wasinvestigated. An initial library consisting of a select group of thecompounds depicted in FIG. 4 and one new compound 5a (SAR 1) wasscreened at 10 μM concentration in cultured human airway epithelialcells (1HAEo-) cells for both antiviral activity and cytotoxicity (seeFIG. 5a : screening for inhibition of RSV infection and cell viabilityas a measure of compound toxicity in the presence of indicated compoundsat 10 μM concentration; 1HAEo-bronchial airway cells were infected withRSV; inoculum media was removed and media containing compounds at 10 μMwas added 2 hours after infection; two days after infection progenyvirus produced by the 1HAEo-cells was collected and Hela indicator cellswere infected; percentage of virus infected HeLa cells was determined byindirect immunofluorescence the following day). From this initial group,compound 5a was identified as a promising candidate, displayingantiviral activity comparable to that of the known antiviralguanosine-analogue drug ribavirin, with no cytotoxicity. This resultguided the selection of compounds for a second focused library (SAR 2),several examples of which included 2-aryl substitution at the 2-positionof the indole nucleophile, and from which several compounds withimproved antiviral activity and minimal toxicity were identified (seeFIG. 6 for structures of 5a-h).

While numerous fusion inhibitors for RSV have been identified, includingthe prophylactic monoclonal antibody Palivizumab, they have yet totranslate into therapy for the treatment of established RSV infections.This may be due to the nature of Palivizumab targeting only the entrystep of the viral replication cycle. Therefore inhibiting the RSVreplication complex after RSV has entered a cell was considered adesirable mechanism of action to block the spread of existing infection.To elucidate a mechanism of antiviral activity, root antiviral compound5a was assayed for activity against the RSV viral replication complexthat serves as a marker of RSV replication in the host cell. Decreasingviral transcription from the RSV replication complex was observed in adose dependent manner in the presence of compound 5a in vitro (see FIG.5b : (Left) in vitro RSV transcription was inhibited by compound 5a; oneday after RSV infection 1HAEo-cells were lysed in transcription buffercontaining ³²P labelled uridine; viral transcripts for RSV Fusion (F),Nucleoprotein (N), Matrix (M) and Phospho (P) proteins were separated ona sequencing gel and the signal was measured after 3-5 days of exposure;(Right) results for 4 independent experiments).

To further assess the therapeutic potential of compounds identified inSAR 1 and SAR 2, a therapeutic index (TI) of each compound wasidentified (e.g., ratio of effective concentration at which viralreplication is reduced by half (EC50) to cytotoxic concentration atwhich cell viability is reduced by half (CC50)). Compound 2p wasincluded as a cytotoxicity control, having demonstrated cytotoxicity inSAR 1. Cell viability decreased rapidly with increasing concentration ofcompound 2p, with a CC50 value of 22.8 μM, while viral replication wasnot diminished at compound concentrations tolerated by the host cell. Incontrast, compound 5a and the 5 series of compounds derived from 5aconsistently inhibited viral replication at concentrations tolerated bythe host cell. In SAR 2, addition of OMe at R¹ decreased the toxicity ofthese compounds, with CC50 values increasing from 42.5 μM for compound5a, to 59.2 μM and 93.5 μM for compounds 5b and 5f respectively.Overall, the TI was increased from 4.1 for compound 5a to 12.3 withcompound 5f. These increases in TI suggested that the compounds werecapable of interfering with viral replication at concentrationstolerated by the host cell.

An established challenge to development of antiviral pharmaceuticals isthe evolution of antiviral resistance. This is pronounced for viruseswith RNA genome due to an inherent error-prone process of RNA-dependentRNA polymerase replication of a viral genome. Error prone replicationresults in a high mutation rate of RNA viruses that leads to developmentof antiviral resistance. As such, development of resistant mutants tocompounds 5a and 5f was undertaken, as the site of mutations couldprovide further insights into the nature of the viral target. However,despite development of resistance against other transcription inhibitorsin 6-8 passages, 14 serial passages over five weeks did not result inthe development of viruses resistant to either compound (see FIG. 5c :no resistance emerged during serial passage of RSV in compounds 5a and5f; 1HAEo-cells infected with RSV; two hours after infection inoculummedia were removed and replaced with media containing compound 5a or 5f;two to three days after infection, the progeny virus was collected fromthe cells and transferred onto a new 1HAEo-monolayer; an aliquot wasstored in liquid nitrogen for quantification via indirectimmunofluorescence). This may suggest that the burden of resistantmutations to evade these compounds is too great, reducing RSV virulencedue to mutagenic catastrophe.

ZIKV constitutes a virus distinct from RSV with a markedly differentintracellular replication strategy. Both viruses encode a viral RdRpessential to viral replication; however, the structure and function ofRSV RdRp and ZIKV RdRp are quite different. RSV is a Pneumoviridaefamily virus with a negative sense RNA genome, and hence RSV RdRp mustbe packaged with an infecting virion for transcription to occur. RSVpolymerase recognizes cis-acting ‘gene start’ and ‘gene end’ elements ofthe viral genome to produce subgenomic mRNAs enabling translation ofviral proteins. In contrast, ZIKV is a Flaviviridae family virus havinga positive sense RNA genome. Therefore, the ZIKV genome can be directlytranslated into one large viral polyprotein by host ribosomes without aneed for production of viral subgenomic mRNAs. Thus the primary functionof ZIKV RdRp is to facilitate genome replication through a negativesense antigenome intermediate. As RSV and ZIKV represent taxonomicallydistinct viruses, antiviral activity of the isatisine A-inspiredbis(indole) compounds were examined against ZIKV to determine whethertheir antiviral activities may be broadly acting. ZIKV infection wasscreened in the presence of compounds 2d, 2o, 5a, and 5a derivatives(5b-5h) in VERO cells. Significant inhibition of ZIKV by compound 5a andall 5a derivatives was observed (see FIG. 5d and e : screening forinhibition of ZIKV infection and cell viability as a measure of compoundtoxicity at 10 μM; A549 cells were infected with ZIKV; inoculum mediawere removed and media containing the compounds at a concentration of 10μM were added four hours after infection; progeny virus was collectedand quantified on Vero cells by titering plaque assay, n=3). These datasuggested that compound 5a and derivatives may hold broad spectrumantiviral activity, providing a broader array of root compounds fromwhich lead compounds can be developed.

As such, a dual catalytic cascade process was discovered that rapidlyassembles drug-like bis(indole) scaffolds under mild, convenientconditions whose only by-products are 2 equiv of N2. Indole trappingagents served to activate a Cu(OTf)₂ precatalyst, while also producing aBronsted acid catalyst required for Friedel-Crafts alkylation of indolesby the intermediate C-acylimines. Preliminary experiments demonstratedthat added chiral acids afforded moderate enantioselectivity. Some ofthe bis(indole) products showed promising antiviral activity againstimportant pathogens RSV and ZIKV. The modular nature of the synthetictransformation may allow for the development of improved analoguesagainst these and other undesirable pathogens.

TABLE 1 Survey of Reaction Conditions

Entry Conditions Yield (%) 2a 1 10 mol % Cu(hfacac)₂; PhMe; reflux42^(a) 2 10 mol % Cu(hfacac)₂; PhMe; rt trace 3 10 mol % CuOTf•PhMe;DCM; rt 12^(b) 4 10 mol % Cu(OTf)₂, DCM, rt, 24 h 92 5 as above,gram-scale 83 (74)^(c) 6. 10 mol % Cu(OTf)₂, DCM, rt, no indole, 72 h 07 10 mol % Cu(0) powder, DCM, rt NR 8 10 mol % Cu(OTf)₂, PhMe, rt, 24 h26 9 10 mol % Cu(OTf)₂, Et₂O, rt, 24 h trace 10 10 mol % Cu(OTf)₂,CHCl₃, rt, 24 h 68^(d) 11 10 mol % Cu(OTf)₂, DCM, 0° C., 24 h trace12^(e) 10 mol % Cu(OTf)₂, L*, PhMe, rt, 24 h trace ^(a)Product isolatedas a mixture of regioisomers. ^(b)1a was rapidly consumed with formationof multiple colored products. ^(c)Gram-scale reaction with directrecrystallization of crude product. ^(d)Multiple colored products wereobserved. ^(e)L* = bis(oxazoline) ligands shown above.

Example 2 Further Experimental Details on Dual Catalytic Synthesis ofAntiviral Compounds Based on Metallocarbene-Azide Cascade ChemistryCompound Stability Studies

Differential Scanning calorimetry (DSC): An example of a DSC experimentfor compound 1a is depicted in FIG. 7. These data show the temperatureat which crystals of 1a began to melt (endotherm, positive peak, 75.5°C.) and began to decompose (exotherm, negative peak, 127° C. to 168°C.). Heat released after decomposition was about 1730 J/g material.

Thermogravimetric analysis (TGA): The decomposition pattern was furthermonitored using a TGA experiment. An example of a TGA experiment forcompound 1a is shown in FIG. 8. It was found that dicarbonyl stabilizeddiazo crystals of 1a generally exhibited one sharp inflection point,starting at temperatures around 130° C., in agreement with the DSCexperiment. No substantial mass change was noticed during the solid toliquid phase transition, indicative of no decomposition of materialduring melting phase transition.

Both of these experiments shed some light on the thermal stability of1a. These experiments provided evidence that the metal catalyzedtransformation, associated with the starting material 1a, at ambienttemperature (22° C. to 40° C.), described in the next section (videinfra), was not merely heat driven as the starting material 1a wasstable at this temperature range. Moreover, using the DSC data, it wasanticipated that there would be less risk of detonation, due to thermalrunaway, associated with compound 1a, or analogous diazoazides, providedthe material was stored at freezer temperature (<0° C.) when not in use.Long-term storage (>1 week) is generally not advisable for compound 1a,especially for a large-scale preparation, but it was noticed thatcompound 1a and the other analogues survived with little or nodecomposition during storage at freezer temperature (−20° C.) for >3months (monitored weekly using ¹H NMR).

These experiments (DSC and TGA) alone should not, however, be taken asan indication that the material is completely safe for handling. Otherparameters, for example potential shock sensitivity, are equallyimportant. Attempts to carry out a hammer test for compound 1a (ca. 0.5mg) to evaluate its shock sensitivity were inconclusive. A small sparkwas observed, but in the absence of a reliable benchmark, it was notpossible to draw any conclusions regarding the shock sensitivity of 1a.Similar to other common potentially explosive materials used in organicsynthesis laboratories, such as peroxides, it is cautioned to potentialusers to treat the starting material 1a and analogues with due care andrespect. Any unanticipated detonation of these diazo azide startingmaterials was not observed, and most large-scale reactions involvingthese substrates were performed in a well-ventilated fume hood equippedwith a blast shield. It is recommended to wear a Kevlar® apron andsafety gloves and using earplugs as added safety precautions, especiallyfor large-scale reactions.

Mechanistic Considerations

Copper Oxidation State in the Catalytic Cycle

Conversion Studies (% Recovery):

Copper (II) oxidation state:

A solution of diazo-azide 1a (50 mg, 0.20 mmol) in DCM (5 mL) was addedto a solution of Cu(OTf)₂ (7.3 mg, 0.020 mmol) in DCM (5 mL) at roomtemperature via syringe pump over 1 h. Once addition was complete, thereaction was monitored by TLC for consumption of the diazo-azidestarting material. After 24 h, the solution was extracted with water (10mL, 3×) to remove the copper salt, and the DCM solution was dried withMgSO₄, filtered and concentrated under reduced pressure. The crude oilwas purified using silica gel flash column chromatography eluting with20% EtOAc/Hexanes. This procedure resulted in recovery of diazo-azide1a, in 81-93% (three repeats). Using identical conditions but allowingthe mixture to stir for 5 d instead of 24 h resulted in recovery of73-84% (three repeats) starting material 1a. Analysis of TLC and NMRspectra of the crude mixture revealed the presence of starting material,and a faint spot on the baseline using 20% EtOAc/Hexanes as the eluent(TLC).

Copper (I) Oxidation State:

A solution of diazo-azide 1a (50 mg, 0.20 mmol) in DCM (5 mL) was addedto a solution of Cu(OTf)(PhMe) (10 mg, 0.020 mmol) in DCM (5 mL) at roomtemperature via syringe pump over 1 h. Once addition was complete, thereaction was monitored by TLC for consumption of the diazo-azidestarting material. After 24 h, the solution was extracted with water (10mL, 3×) to remove the copper salt, the DCM solution was dried withMgSO₄, filtered and concentrated under reduced pressure. The crude oilwas purified using silica gel flash column chromatography eluting with20% EtOAc/Hexanes. This procedure resulted in recovery of trace amountof 1a (<5%). Analysis of a TLC chromatogram of the crude mixturerevealed the presence of multiple colored spots. A crude NMR spectrarevealed an intractable mixture of multiple compounds.

Conversion Studies (in-Situ IR Analysis and ¹H-NMR Spectroscopy)

Copper (II) Oxidation State:

Using IR Spectroscopy:

A solution of diazo-azide 1a (50 mg, 0.20 mmol) in DCM (5 mL) was addedto a solution of Cu(OTf)₂ (7.6 mg, 0.02 mmol) in DCM (5 mL) at roomtemperature via syringe pump over 1 h. Once addition was complete, thereaction was monitored by TLC for consumption of the diazo-azidestarting material. An aliquot of the stirred solution (0.5 mL), wastaken after ca. 5 min, 1 h, 2 h, 3 h, and 24 h of stirring, each aliquotwas diluted with DCM (1 mL). The diluted solution was analyzed using IRspectroscopy and plotted as overlaid spectra (FIG. 9a ).

Copper (I) Oxidation State:

A solution of diazo-azide 1a (50 mg, 0.20 mmol) in DCM (5 mL) was addedto a solution of Cu(OTf)(PhMe) (10 mg, 0.020 mmol) in DCM (5 mL) at roomtemperature via syringe pump over 1 h. Once addition was complete, thereaction was monitored by TLC for consumption of the diazo-azidestarting material. An aliquot of the stirred solution (0.5 mL), wastaken after ca. 5 min, 1 h, 2 h, 3 h and 24 h of stirring, each aliquotwas diluted with DCM (1 mL). The diluted solution was analyzed using IRspectroscopy and plotted as overlaid spectra (FIG. 9b ).

A complete absence of a broad peak at 2137 cm⁻¹ indicated completedecomposition of the diazoketone and the azide functional groups. Anincrease in the absorbance and broadening of signal around 1730 cm⁻¹ wasnoticed on diazo-azide starting material upon exposure with copper (II)triflate over 24 h, indicative of carbonyl interaction (dative bond)with copper (II), which did not progress to substantial diazo-ketonedecomposition (notice continued substantial absorbance at 2137 cm-1).However, a notable decrease in the absorbance of the signal around 2137cm⁻¹ was noticed on diazo-azide starting material upon exposure withcopper (I) triflate over 24 h, indicative of complete decomposition ofdiazoketone and azide over a 24 h period. This time period is within theobserved optimized reaction time (16-36 h, depending on substitution ofindole substrate) for azide-metallocarbene coupling, followed byFriedel-Crafts alkylation with indole. This pair of experiments,together with the recovery analysis, and ¹H-NMR spectroscopy (videinfra) provided a distinction between the catalytic behaviors of the twocopper oxidation states.

Using ¹H-NMR Spectroscopy:

In a 2.0 mL vial, a solution of diazo-azide 1a (10 mg, 0.040 mmol) indeuterated DCM (0.5 mL) at room temperature was added to Cu(OTf)(PhMe)(ca. 2.0 mg, 0.0039 mmol) as a solid. The solution was quicklytransferred in an NMR tube, capped with septum, and purged with argon.NMR spectra (400 MHz) were acquired once per hour over a 10 h period.The array of spectra was plotted. After 8-10 h, the starting material 1awas completely consumed. These data, corroborated with the IR results,provided evidence that copper (I) was the kinetically competentoxidation state during conversion of diazoazide into C-acylimine (seeFIG. 10).

After extensive analysis of the copper oxidation state necessary fordecomposition of starting material 1a, it was posited that copper (I)was the kinetically competent oxidation state. This, however, was notexpected since the initially loaded catalyst was copper (II) triflate.

Formation of Active Copper (I) Catalyst from Copper (II) Precatalyst

Using UV Spectroscopy, Formation of a New σ-Copper Indole Complex:

Solution A: A solution of indole (55 mg, 0.20 mmol) was added toCu(OTf)₂ (7.3 mg, 0.020 mmol) in DCM (5 mL) at room temperature. Onceaddition was complete, formation of light green solution occurred after1 h. An aliquot of this solution (1 mL) was diluted with 5 mL of DCM andwas subjected to UV spectroscopy. Solution B: An aliquot (1 mL) of asolution of indole dissolved in DCM (0.02 M, 10 mL) at room temperaturewas also subjected to UV spectroscopy. Solution C: An aliquot (1 mL) ofa solution of Cu(OTf)₂ dissolved in DCM (0.02 M, 10 mL) at roomtemperature was also subjected to UV spectroscopy. Further dilution wasnecessary until peaks (>300 nm) could be seen. After analysis of thethree spectra, formation a broad new peak at 395 nm was seen fromSolution A, indicating formation of a new colored complex (FIG. 11).This new peak at 395 nm did not persist and generally had low relativeconcentration. Hence, a concentrated reaction mixture was needed toobserve the absorption at 395 nm. Notably, similar copper-indole specieswas detected by Toste et. al. upon mixing of Cu(II) chiral phosphate andindole [Rauniyar, V.; Wang, Z. J.; Burks, H. E.; Toste, F. D. J. Am.Chem. Soc. 2011, 133, 8486-8489].

Using ESI-MS, Detection of the Mass Fragments Corresponding to theDdimer and the Copper-Indole Complex:

A solution of indole (55 mg, 0.20 mmol) was added to Cu(OTf)₂ (7.3 mg,0.020 mmol) in DCM (5 mL) at room temperature. Once addition was done,formation of light green solution occurred after one hour. An aliquot ofthis solution (1 mL) was diluted with acetonitrile and directlysubjected to ESI-MS analysis. After analysis of the ESI-MS (FIG. 12),the following fragments were detected and partially ascribed to theformation: A HRMS calc'd for C₉H₆CuF₃NO₃S [M]+327.9316, found 327.9645(fleeting), for B HRMS calc'd for C₁₆H₁₄N₂O [M+H]+235.1230, found235.1230, and protonated and sodiated 2a. NB.: Compound B was likewisedetected in crude reaction mixture to make 2a.

Given an apparent reaction between the indole and copper (II) triflateto afford an initially colored complex, the absorption detected throughUV-VIS spectroscopy, and literature precedent [Rauniyar, V.; Wang, Z.J.; Burks, H. E.; Toste, F. D. J. Am. Chem. Soc. 2011, 133, 8486-8489],it was posited reduction of copper (II) triflate through the initiallyformed metallated indole, followed by disproportionation reaction. Thisdisproportation reaction could theoretically generate copper (I)triflate, and copper (III) triflate indole complex. The latter couldreductively eliminate to copper (I) triflate and indole triflate. Basedon these experiments, the kinetically competent copper (I) triflate wasproposed to result from a redox process involving copper (II)precatalyst and indole. However, this proposal on its own could notexplain the substantial difference in isolated yield of 2a betweenCu(OTf)₂ and CuOTf. An additional component in the reaction, presumablyderived from the activation reaction of Cu(OTf)₂ and indole, wasnecessary for efficient Friedel Crafts alkylation with indole. It wasproposed that a Bronsted acid catalyst, either TfOH or its salt withindole dimer B, acted to catalyze Friedel-Crafts addition of indole tothe intermediate C-acylimine formed from metallocarbene-azide coupling.

Evidence for Bronsted Acid Catalysis of Friedel-Crafts Alkylation

NOTE: Since the putative C-acylimine occuring in the Cu(I)-catalyzedcoupling step was transient and could not be isolated, isolableC-acylimine 6 was used as a model to help understand the secondcatalytic cycle.

Stirring C-acylimine 6 with Indole in the Presence of Cu(OTf)(PhMe):

A solution of C-acylimine 6 (50 mg, 0.19 mmol) and indole (50 mg, 0.20mmol) was added to Cu(OTf)(PhMe) (9.7 mg, ca 0.020 mmol) in DCM (5 mL)at room temperature. Once addition was complete, the solution wasallowed to stir overnight. After stirring for 16 h, the solution wasextracted with water (5 mL, 2×), and the organic layer was dried withMgSO₄, filtered and concentrated under reduced pressure. Analysis ofcrude reaction mixture indicated that substantial quantities of 6 werepresent. Upon purification via a short pad of silica (20%EtOAc/Hexanes), ca. 91% of 6 was recovered. This model reaction showedthat, although copper (I) triflate could convert 1a to the C-acylimine(see previous experiments), copper (I) could not efficiently catalyzethe Friedel-Crafts alkylation reaction with indole.

Stirring C-Acylimine 6 with Indole in the Presence of TfOH:

A solution of C-acylimine 6 (50 mg, 0.19 mmol) and indole (50 mg, 0.20mmol) was mixed with excess TfOH (ca. 50 μL, ca. 0.57 mmol) in DCM (5mL) at room temperature. Once mixing was complete, within 5 minutes achange in color was noticed, from deep purple to light orange. Thesolution was diluted with water (5 mL) and extracted with DCM (5 mL,3×). The organic layer was dried using MgSO₄ concentrated under reducedpressure. Analysis of the crude mixture indicated that 6 was completelyconsumed, and adduct 7 can be detected using crude NMR. Purification of7, however, was hampered by the presence of several side products.

Stirring C-Acylimine 6 with Indole in the Presence of CSA:

A solution of C-acylimine 6 (50 mg, 0.19 mmol) and indole (50 mg, 0.20mmol) was mixed with camphorsulfonic acid CSA (4.0 mg, ca. 0.020 mmol)in DCM (5 mL) at room temperature. Once addition was complete, thesolution gradually (overnight) changed color from deep purple to ayellow suspension. Analysis of the TLC indicated that 6 was completelyconsumed. The suspension was filtered. The filtered solid was dissolvedin deuterated DMSO and was analyzed using NMR spectroscopy. Analysis ofthe spectra revealed that the 2:1 adduct, 7, (indole:indol-3-one), alongwith water and DMSO, were the only detectable components present insolution.

These results indicates that Bronsted acid, produced during thereduction of copper (II) triflate by indole, could activate theC-acylimine towards Friedel-Crafts alkylation reaction.

Using a (+)-Camphorsulfonic Acid as a Chiral Co-Catalyst:

A solution of diazo-azide 1a (50 mg, 0.20 mmol) in DCM (5 mL) was addedto a solution of indole (46 mg, 0.39 mmol), Cu(OTf)₂ (7.3 mg, 0.020mmol), and the (+)-CSA (4.0 mg, ca. 0.02 mmol) in DCM (5 mL) at roomtemperature via syringe pump over 1 h. The reaction mixture turned lightgreen over 2 h, then slowly turned dark brown over 24 h. Once additionwas complete, the reaction was monitored by TLC for consumption of 1a.Upon consumption of 1a, the reaction mixture was poured in an Erlenmeyerflask, thoroughly dissolved in ethyl acetate (ca 10 mL), dried overMgSO₄, filtered, concentrated under reduced pressure and purified byflash chromatography. (NB.: crude mixture after concentration wasinsoluble in DCM. In this case, necessarily, ethyl acetate was used as asolvent to load the sample onto silica gel (silica gel, 7:3hexanes:EtOAc). All pure fractions of 2a were concentrated together toafford yellow oil. Upon standing for at least 24 hours, this oil slowlyformed a yellow solid. Analysis of the yellow oil using chiral HPLCrevealed that the product was formed in a 68:32 enantiomeric ratio. HPLCcondition: Chiralpak AD-H, 80:20, Hexanes:i-PrOH, rt, retentiontime=33.77 min (major), 37.71 min (minor).

X-Ray Crystallographic Data

The X-ray crystallographic data depicted in FIG. 13-16 entails ORTEPstructures of select compounds:

ORTEP structure for compound 1a (FIG. 13): Compound-Methyl2-diazo-3-(2-azido-3-methylphenyl)-3-oxopropanoate; Formula-C₁₁H₉N₅O₃.

ORTEP Structure for compound 2a (FIG. 14): Compound-Methyl3-oxo-1,3-dihydro-1′H,2H-2,3′-biindole-2-carboxylate;Formula-C₁₈H₁₄N₂O₃.

ORTEP Structure for compound 2o (FIG. 15): Compound-Methyl6-chloro-3-oxo-1,3-dihydro-1′H,2H-2,3′-biindole-2 carboxylate;Formula-C₁₈H₁₃ClN₂O₃.

ORTEP Structure for compound 2za (FIG. 16): Compound-(−)-Menthyl(2R)-1′-benzyl-3-oxo-1,3-dihydro-1′H,2H-2,3′-biindole-2-carboxylate;Formula-C₃₄H₃₆N₂O₃.

NMR Spectra of the Starting Materials and Products

Please see FIG. 17-54.

The presence of significant signals for residual water in the ¹H NMRspectra of 2a, 2e, 2l, 2o, 2t and 2v may raise questions about proof ofpurity. It should be noted that the presence of one or more heavyhalogen atoms and/or an unprotected indole nitrogen atom rendered thesecompounds only sparingly soluble in common deuterated NMR solvents(CDCl₃, CD₂Cl₂, C₆D₆, C₃D₆O, CD₃OD, and C₂D₆SO). Consequently, minoramounts of water contaminant in these solvents may appear to haveanomalously enhanced signals relative to those of the compounds ofinterest. ¹H NMR spectra of these compounds were not representative ofthe bulk material, and cannot be used as the sole judge or proof ofpurity.

However, the following observations from data presented above werereasonable proof of purity, apart from the ¹H-NMR spectra presented inthe next section: (i) reasonable accuracy of experimental elementalanalysis (C, H, and N) compared to theoretical value (0.05-0.34%) inthose cases where combustion analysis was performed; (ii) sharp (1-3°C.) and high (>100° C.) melting points; (iii) substantially highermelting points compared to reported literature value (2a and 2b)[Jessing, M.; Barran, P. S. Heterocycles 2011, 82, 1739-1745]; and, highdegree of crystallinity, and with X-ray crystal structures andmeasurements for 2a, 2o, and 2za.

Example 3

A model of a Respiratory Syncytial Virus (RSV) L protein was built,using SWISS-MODEL (on the internet at swissmodel(dot)expasy(dot)org).Figures obtained using Chimera and Pymol.

RSV L protein is an RNA-directed RNA polymerase.

Molecular dynamic simulations were carried out to refine the model usingNAMD on Graham clusters (Compute Canada). Molecular docking experimentswere performed using the Schrödinger Small Molecule Discovery Suite andfigures obtained using Pymol. The results are depicted in FIG. 55 andFIG. 56.

FIG. 55 depicts homology modelling of the RSV L protein based off theVSV L structure. Model of RSV L protein (left), Alignment of the RSVmodel with L protein of VSV. (VSV: Vesicular Stomatitis Virus).

FIG. 56 depicts molecular docking of the active compound (compound 5a)into the active site of RSV L protein showing two hydrogen bonds to thecatalytic ASP 686. The active site was defined using binding site mapimplanted in Schrödinger Small Molecule Discovery Suite.

REFERENCES

(1) (a) Padwa, A.; Weingarten, M. D. Chem. Rev. 1996 96,223-270. (b)Doyle, M. P.; McKervey, M. A.; Ye, T. Modern Catalytic Methods forOrganic Synthesis with Diazo Compounds: From Cyclopropanes to Ylides;Wiley: New York, 1998.

(2) (a) Padwa, A.; Hornbuckle, S. F. Chem. Rev. 1991, 91, 263-309. (b)Vanecko, J. A.; Wan, H.; West, F. G.; Tetrahedron 2006, 62, 1043-1062.(c) Murphy, G. K.; Stewart, C.; West, F. G. Tetrahedron 2013, 69,2667-2686.

(3) Bott, T. M.; Atienza, B. J.; West, F. G. RSC Adv. 2014, 4,31955-31959.

(4) Liu, J. F.; Jiang, Z. Y.; Wang, R. R.; Zheng, Y. T.; Chen, J. J.;Zhang, X. M.; Ma, Y. B. Org. Lett. 2007, 9, 4127-4129.

(5) (a) Karadeolian, A.; Kerr, M. A. J. Org. Chem. 2010, 75, 6830-6841.(b) Karadeolian, A.; Kerr, M. A. Angew. Chem. Int. Ed. 2010, 49,1133-1135. (c) Lee, J.; Panek, J. S. Org. Lett. 2011, 13, 502-505. (d)Lee, J.; Panek, J. S. J.Org. Chem. 2015, 80, 2959-2971. (e) Zhang, X.;Mu, T.; Zhan, F.; Ma, L.; Liang, G. Angew. Chem. Int. Ed. 2011, 50,6164-6166. (f) Wu, W.; Xiao, M.; Wang, J.; Li, Y.; Xie, Z. 9 Org. Lett.2012, 14, 1624-1627. (g) Patel, P.; Ramana, C. V. I Org. Chem. 2012, 77,10509-10515. (h) Xiao, M.; Wu, W.; Wei, L.; Jin, X.; Yao, X.; Xie, Z.Tetrahedron 2015, 3705-3714.

(6) Nair, H.; Nokes, D. J.; Gessner, B. D.; Dherani, M.; Madhi, S. A.;Singleton, R. J.; O'Brien, K. L.; Roca, A.; Wright, P. F.; Bruce, N.;Chandran, A.; Theodoratou, E.; Sutanto, A.; Sedyaningsih, E. R.; Ngama,M.; Munywoki, P. K.; Kartasasmita, C.; Simoes, E. A.; Rudan, I.; Weber,M. W.; Campbell, H. Lancet 2010, 375, 1545-1555.

(7) Faria, N. R.; Azevedo Rdo, S.; Kraemer, M. U.; Souza, R.; Cunha, M.S.; Hill, S. C.; Theze, J.; Bonsall, M. B.; Bowden, T. A.; Rissanen, I.;Rocco, I. M.; Nogueira, J. S.; Maeda, A. Y.; Vasami, F. G.; Macedo, F.L.; Suzuki, A.; Rodrigues, S. G.; Cruz, A. C.; Nunes, B. T.; Medeiros,D. B.; Rodrigues, D. S.; Nunes Queiroz, A. L.; da Silva, E. V.;Henriques, D. F.; Travassos da Rosa, E. S.; de Oliveira, C. S.; Martins,L. C.; Vasconcelos, H. B.; Casseb, L. M.; Simith Dde, B.; Messina, J.P.; Abade, L.; Lourenco, J.; Carlos Junior Alcantara, L.; de Lima, M.M.; Giovanetti, M.; Hay, S. I.; de Oliveira, R. S.; Lemos Pda, S.; deOliveira, L. F.; de Lima, C. P.; da Silva, S. P.; de Vasconcelos, J. M.;Franco, L.; Cardoso, J. F.; Vianez-Junior, J. L.; Mir, D.; Bello, G.;Delatorre, E.; Khan, K.; Creatore, M.; Coelho, G. E.; de Oliveira, W.K.; Tesh, R.; Pybus, O. G.; Nunes, M. R.; Vasconcelos, P. F., Science2016, 352, 345-349.

(8) Mlakar, J.; Korva, M.; Tul, N.; Popovic, M.; Poljsak-Prijatelj, M.;Mraz, J.; Kolenc, M.; Resman Rus, K.; Vesnaver Vipotnik, T.; FabjanVodusek, V.; Vizjak, A.; Pizem, J.; Petrovec, M.; Avsic Zupanc, T. NEngl. J. Med. 2016, 374, 951-958.

(9) Salomon, R. G.; Kochi, J. K. J. Am. Chem. Soc. 1973, 95, 3300-3310.

(10) Despite the high nitrogen content of substrate 1a, we have notobserved explosive decomposition under standard conditions. Analysis byDSC and TGA indicate thermal instability above 127° C. (See SupportingInformation). Nonetheless, use of a blast shield and appropriateprotective wear (earplugs, Kevlar lab coat and gloves) is recommendedfor gram-scale reactions.

(11) Phipps, R. J.; Grimster, N. P.; Gaunt, M. J. J. Am. Chem. Soc.2008, 130, 8172-8174.

(12) Ribas, X.; Jackson, D. A.; Donnadieu, B.; Mahia, J.; Parella, T.;Xifra, X.; Hedman, B.; Hodgson, K. O.; Llobet, A.; Stack, T. D. P.Angew. Chem. Int. Ed. 2002, 41, 2991-2994.

(13) When the conditions of Table 1, entry 4 were carried out in thepresence of various bases (pyridine, triethylamine, various inorganicbases), no conversion was observed. While these results are consistentwith the Bronsted acid requirement, they may also be attributable toinhibition of the initial redox activation step by base coordination toCu(II).

(14) (a) Aburatani, S.; Uenishi, J. Heterocycles 2008, 75, 1407-1416.(b) Quartarone, G.; Charmet, A. P.; Ronchin, L.; Tortato, C.; Vavasori,A. J. Phys. Org. Chem. 2014, 27, 680-689. (c) Guo, T.; Han, S.-L.; Liu,Y.-C.; Liu, H.-M. Tetrahedron Lett. 2016, 57, 1097-1099.

(15) (a) Suárez-Castillo, O. R.; Mélendez-Rodriguez, M.; Morales-Garcia,A. L.; Cano-Escudero, I. C.; Contreras-Martinez, Y. M. A.; Moreles-Rios,M. S.; Joseph-Nathan, P. Heterocycles 2009, 78, 1463-1476. (b) Xu,X.-H.; Liu, G.-K.; Azuma, A.; Tokunaga, E.; Shibata, N. Org. Lett. 2011,13, 4854-4857.

(16) For related indole additions to an indolenones catalyzed by chrialBrønsted acid, see: (a) Rueping, M.; Raja, S.; Nunez, A. Adv. Synth.Catal. 2011, 353, 563-568. (b) Yin, Q.; You, S.-L. Chem. Sci 2011, 2,1344-1348.

(17) Sun, Z.; Pan, Y.; Jiang, S.; Lu, L. Viruses 2013, 5, 211-225.

(18) Chapman, J.; Abbott, E.; Alber, D. G.; Baxter, R. C.; Bithell, S.K.; Henderson, E. A.; Carter, M. C.; Chambers, P.; Chubb, A.; Cockerill,G. S.; Collins, P. L.; Dowdell, V. C.; Keegan, S. J.; Kelsey, R. D.;Lockyer, M. J.; Luongo, C.; Najarro, P.; Pickles, R. J.; Simmonds, M.;Taylor, D.; Tyms, S.; Wilson, L. J.; Powell, K. L. Antimicrob. AgentsChemother. 2007, 51, 3346-3353.

(19) Noton, S. L.; Fearns, R. Virology 2015, 479-480C, 545-554.

(20) Selisko, B.; Wang, C.; Harris, E.; Canard, B. Curr. Opin. Virol.2014, 9, 74-83.

(21) Jessing, M.; Barran, P. S. Heterocycles 2011, 82, 1739-1745.

(22) Hallak, L. K.; Spillmann, D.; Collins, P. L.; Peeples, M. E. J.Virol. 2000, 74, 10508-10513.

(23) Canter, D. M.; Jackson, R. L.; Perrault, J. Virology 1993, 194,518-529.

(24) Noton, S. L.; Nagendra, K.; Dunn, E. F.; Mawhorter, M. E.; Yu, Q.;Fearns, R. J. Virol. 2015, 89, 7786-7798.

The embodiments described herein are intended to be examples only.Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art. The scope of theclaims should not be limited by the particular embodiments set forthherein, but should be construed in a manner consistent with thespecification as a whole.

All publications, patents and patent applications mentioned in thisSpecification are indicative of the level of skill those skilled in theart to which this invention pertains and are herein incorporated byreference to the same extent as if each individual publication patent,or patent application was specifically and individually indicated to beincorporated by reference.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodification as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A compound of formula (I)

or a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptable salt, a solvate, or a functional derivative thereof, wherein: R¹ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; R² is independently aryl, benzyl, or heterocycle, each of which is optionally substituted; and R³ and R⁴ are each independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or R³ and R⁴, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted.
 2. The compound of claim 1, having the formula (II)

or a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptable salt, a solvate, or a functional derivative thereof, wherein: Y is independently C or a heteroatom; R¹ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₂₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; R³ and R⁴ are each independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or R³ and R⁴, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted; and R⁶ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁶, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted; and wherein one Y is bonded to C₁ and the corresponding R⁶ is absent.
 3. The compound of claim 1 or 2, having the formula (III)

or a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptable salt, a solvate, or a functional derivative thereof, wherein: Y and Y′ are each independently C or a heteroatom; R¹ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁵, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted; and R⁶ is independently H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁶, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted; and wherein one Y′ is bonded to C₁ and the corresponding R⁶ is absent.
 4. The compound of claim 1, having the formula (IV)

or a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptable salt, a solvate, or a functional derivative thereof, wherein: Y is independently C or a heteroatom; R¹ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁵, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted; and R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₁₀-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₁₀-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁷, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted.
 5. The compound of claim 1, having the formula (V)

or a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptable salt, a solvate, or a functional derivative thereof, wherein: Y is independently C or a heteroatom; R¹ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; R⁵ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁵, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted; R⁷ is independently absent, H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₁₀-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₁₀-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁷, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted; and, R⁸ is independently H, C₁-C₁₀ alkyl, C₂-C₂₀ alkyl, C₂-C₁₀ alkenyl, C₂-C₂₀ alkenyl, C₂-C₁₀ alkynyl, C₂-C₂₀ alkynyl, C₃-C₂₀ carbocycle, aryl, benzyl, heterocycle, C₁-C₁₀ alkoxy, C₂-C₂₀ alkoxy, alcohol, ether, ketone, carboxylic acid, ester, thiol, thioether, amine, amide, carbamate, nitro, cyano, or halo, each of which is optionally substituted; or two of R⁸, together with the atoms to which they are attached, are connected to form a cycle or heterocycle, each of which is optionally substituted.
 6. The compound of claim 1, having the formula (VI)

or a stereoisomer, a racemate, a tautomer, a pharmaceutically acceptable salt, a solvate, or a functional derivative thereof, wherein: R¹ is an ester; R⁵ is a halo; and, R⁸ is independently H, C₁-C₁₀ alkoxy, or halo, each of which is optionally substituted.
 7. The compound of claim 1, having the structure


8. The compound of claim 1, having the structure


9. A method of synthesizing a compound of any one of claims 1 to 8, comprising: a) reacting an organoazide-dizaoketone compound with a transition metal catalyst b) forming a metallocarbene from the reaction of the organoazide-dizaoketone compound with a transition metal catalyst; c) generating an electrophilic C-acylimine from the metallocarbene; and d) reacting the electrophilic C-acylimine with a nucleophilic compound.
 10. The method of claim 9, wherein step d) further comprises reacting the electrophilic C-acylimine with a nucleophilic compound in the presence of a Bronsted acid catalyst.
 11. The method of claim 9, wherein the transition metal catalyst is a Cu catalyst.
 12. The method of claim 11, wherein the transition metal catalyst is Cu(hfacac)₂, Cu(OTf)₂, or CuOTf.Ph(CH₃).
 13. The method of claim 9, wherein the nucleophilic compound is a heteroatom-containing compound.
 14. The method of claim 13, wherein the heteroatom-containing compound is a heterocycle or a cycle substituted with a heteroatom-containing moiety.
 15. The method of claim 14, wherein the heterocycle is pyrrole, furan, thiophene, pyridine, indole, benzofuran, benzothiphene, imidazole, or derivatives thereof, each of which is optionally substituted.
 16. A pharmaceutical composition comprising a compound of any one of claims 1 to 8, or a compound syntheized by the method of any one of claims 8 to 15, and a pharmaceutically acceptable carrier, diluent, or vehicle.
 17. A method of treating a subject having or suspected of having an infectious disease, comprising: administering a therapeutically effective amount of a compound of any one of claims 1 to 8, or a compound syntheized by the method of any one of claims 8 to 15, or a pharmaceutical composition of claim
 16. 18. A method of treating a subject having or suspected of having an infectious disease, comprising: administering a therapeutically effective amount of a compound of any one of claims 1 to 8, or a compound syntheized by the method of any one of claims 8 to 15, or a pharmaceutical composition of claim 16, wherein said infectious disease is caused by a virus.
 19. The method of claim 18, wherein said virus is a virus from the family Flaviviridae.
 20. The method of claim 19, wherein the virus is from the genera Hepacivirus, Flavivirus, Pegivirus, or Pestivirus.
 21. The method of claim 20, wherein said flavivirus is yellow fever virus (YFV), Japanese encephalitis virus (JEV), Tick-borne encephalitis virus (TBEV), Dengue virus (DENV), West Nile virus (WNV), Zika virus (ZIKAV), or any combination thereof.
 22. The method of claim 18, wherein said virus is from the family Paramyxoviridae.
 23. The method of claim 22, wherein said virus is from the genera Paramyxovirus, Pneumovirus, or Morbillivirus.
 24. The method of claim 23, wherein Paramyxovirus is parainfluenza virus or mumpus virus.
 25. The method of claim 23, wherein said Pneumovirus is respiratory syncytial virus (RSV).
 26. The method of claim 23, wherein said Morbillivirus is measles virus.
 27. The method of claim 17, wherein said subject is a human, a domesticated animal, livestock, a laboratory animal, a non-human mammal, a non-human primate, a rodent, a bird, a reptile, an amphibian, or a fish.
 28. Use of a compound of any one of claims 1 to 8, or a compound syntheized by the method of any one of claims 8 to 15, or a pharmaceutical composition of claim 16 for treating a subject having or suspected of having an infectious disease.
 29. Use of a compound of any one of claims 1 to 8, or a compound syntheized by the method of any one of claims 8 to 15, or a pharmaceutical composition of claim 16 in the manufacture of a medicament for treating a subject having or suspected of having an infectious disease.
 30. Use of a compound of any one of claims 1 to 8, or a compound syntheized by the method of any one of claims 8 to 15, or a pharmaceutical composition of claim 16 for treating a subject having or suspected of having an infectious disease, wherein said infectious disease is caused by a virus.
 31. Use of a compound of any one of claims 1 to 8, or a compound syntheized by the method of any one of claims 8 to 15, or a pharmaceutical composition of claim 16 in the manufacture of a medicament for treating a subject having or suspect of having an infectious disease, wherein said infectious disease is caused by a virus.
 32. The use of claim 30 or 31, wherein said virus is a virus from the family Flaviviridae.
 33. The use of claim 32, wherein the virus is from the genera Hepacivirus, Flavivirus, Pegivirus, or Pestivirus.
 34. The use of claim 33, wherein said flavivirus is yellow fever virus (YFV), Japanese encephalitis virus (JEV), Tick-borne encephalitis virus (TBEV), Dengue virus (DENV), West Nile virus (WNV), Zika virus (ZIKAV), or any combination thereof.
 35. The use of claim 30 or 31, wherein said virus is a virus from the family Paramyxoviridae.
 36. The use of claim 35, wherein said virus is from the genera Paramyxovirus, Pneumovirus, or Morbillivirus.
 37. The use of claim 36, wherein Paramyxovirus is parainfluenza virus or mumpus virus.
 38. The use of claim 36, wherein said Pneumovirus is respiratory syncytial virus (RSV).
 39. The use of claim 36, wherein said Morbillivirus is measles virus.
 40. The use of any one of claims 28 to 39, wherein said subject is a human, a domesticated animal, livestock, a laboratory animal, a non-human mammal, a non-human primate, a rodent, a bird, a reptile, an amphibian, or a fish.
 41. A method of inhibiting an RNA-dependent RNA polymerase (RdRP) of an RNA virus, the method comprising contacting the RdRP with a compound according to any one of claims 1-8. 